home automation with arduino: automate your … automation with arduino automate your home using...

HomeAutomationWithArduinoAutomateYourHomeUsingOpen-SourceHardware

MarcoSchwartz,PhD

ContentsLegalAcknowledgmentsAbouttheauthorAboutthecompanionwebsitePrefacetotheFirstEditionPrefacetotheThirdEditionIntroduction

1 HowistheBookOrganized?2 WhyOpen-Source?3 Whatwillyoulearn?4 Safetyconcerns5 Prerequisites

Chapter1 GettingStarted1.1 TheArduinoPlatform1.2 WhatyouNeedtoKnowAboutElectronics1.3 YourVeryFirstProject:aSimpleAlarmSystem

Chapter2 BuildingaWeatherMeasurementStation2.1 Hardware&SoftwareRequirements2.2 HardwareConfiguration2.3 TestingtheSensors2.4 DisplayingtheDataontheLCDScreen2.5 HowtoGoFurther

Chapter3 BuildingaSmartLamp3.1 Hardware&SoftwareRequirements3.2 HardwareConfiguration3.3 TestingtheRelay3.4 PowerMeasurements&AutomaticLightingControl3.5 HowtoGoFurther

Chapter4 XBeeMotionSensors4.1 Hardware&SoftwareRequirements4.2 BuildinganXBeeMotionSensor4.3 TestingtheMotionSensor4.4 UsingtheXBeeModule4.5 BuildingtheCentralInterface4.6 HowtoGoFurther

Chapter5 BluetoothWeatherStation5.1 Hardware&SoftwareRequirements5.2 BuildingtheBluetoothWeatherStation5.3 PairingtheBluetoothModule5.4 RemoteTemperatureMeasurements5.5 BuildingtheServerInterface5.6 HowtoGoFurther

Chapter6 ControllingLampsviaWiFi6.1 Hardware&SoftwareRequirements6.2 BuildingtheProject6.3 TestingtheWiFiModule6.4 RemoteLampControl6.5 BuildingtheSmartLampInterface6.6 HowtoGoFurther

Chapter7 BuildinganHomeAutomationSystem7.1 Hardware&SoftwareRequirements7.2 BuildingtheProject7.3 TestingtheModules7.4 BuildingtheCentralInterface7.5 HowtoGoFurther

Chapter8 Conclusion8.1 Whatdidyoulearninthisbook?8.2 Howtogofurther?

Chapter9 Resources9.1 GeneralInformationaboutArduino9.2 Components9.3 SuggestedReading

LegalCopyright©2014byMarc-OlivierSchwartz

Allrightsreserved. Nopartofthisbookmaybeusedorreproducedinanymannerwhatsoeverwithoutpermissionexceptinthecaseofbriefquotationsembodiedincriticalarticlesorreviews.

ThirdeBookedition:August2014

AcknowledgmentsToallmyfriendswhoencouragedmewhilewritingthisbookandworkingonallmyprojects.

Tomyparentswhosupportedmewhilewritingthisbook,andwhosupportedmeduringalltheotherprojectsImadeinmylife,evenintoughtimes.

TomygirlfriendSylwiaforsupportingmeandencouragingmeineverythingIdo. YouaremysourceofinspirationIneedtogetupeverydayandcontinuetoworkhardtobecomeabetterentrepreneurandabetterperson. Thankyou.

AbouttheauthorIamMarcoSchwartz,andIamanelectricalengineer,entrepreneurandauthor. IhaveaMaster’sdegreeinElectricalEngineering&ComputerSciencefromoneofthetopElectricalEngineeringschoolinFrance,andaMaster’sdegreeinMicroEngineeringfromtheEPFLuniversityinSwitzerland.

Ihavemorethan5yearsofexperienceworkinginthedomainofelectricalengineering.Myinterestsgravitatearoundelectronics,homeautomation,theArduinoplatform,open-sourcehardwareprojects,and3Dprinting.

Since2011Ihavebeenworkingfull-timeasanentrepreneur,runningwebsiteswithinformationaboutopen-sourcehardwareandbuildingmyownopen-sourcehardwareproducts.

AboutthecompanionwebsiteThisbookhasacompanionwebsite,OpenHomeAutomation,whichyoucaneasilyfindbygoingathttp://www.openhomeautomation.net. Onthiswebsiteyouwillfindevenmoreprojectsandresourcesaroundhomeautomationandopen-sourcehardware.

Allthecodethatcanbefoundinthisbookcanalsobeaccessedonlineathttps://github.com/openhomeautomation/home-automation-arduino. ThisGitHubrepositoryforthebookcontainsallthelatestup-to-datecodeforalltheprojectsyouwillfindinthisbook.

http://www.openhomeautomation.net

https://github.com/openhomeautomation/home-automation-arduino

PrefacetotheFirstEditionIwasintroducedtothefascinatingworldofhomeautomationwhileIwasvisitingthehomeofoneofmyrichfriends. Iwassurprisedbyhoweasyitallseemed:lightswouldactivatethemselvesautomaticallywhenitwasstartingtogetdark,temperatureswereautomaticallymeasuredineveryroomofthehouseandsenttoacentralserver,andthestatusofeveryalarmsensorofthehousecouldbemonitoredfromacellphone. Buttheproblematthattimewashuge:thesolutionsweretailoredforthathousebyprivatecompanies,andthereforeitwasreservedonlytowealthypeople. Andthisisstillanideathatisaroundnowadays:homeautomationcostsalot.

Ipersonallyhaveanotherproblemwithsuchsystems:youdon’thaveanycontrolofthem.Youhavetofolloweverythingthemanufacturerhasdecidedforyou:themaincontroller,thesensors,thesoftware. Forexample,ifonesensorisfailinginyoursystem,youhavetoreplaceitwithasensorfromthesamebrand. IrememberwhenIwasusingoneofthesecommercialsystemsatafriend’shouse. Ialwayswantedtochangesomething:makeasensoreasiertouse,fixabugintheinterface…butIcouldn’t.

Ofcourse,theideaofbuildingyourownhomeautomationsystemhasalwaysbeenaround. Irememberplayingwithmyfirstmicrocontrollerin2003,anditwasactuallyquiteeasy…ifyouwereintheengineeringworld. Thesesystemswerequiteclosed,andeachofthemrequiredlearningspecificknowledgeabouttheplatform. Andevaluationkitsforthesemicrocontrollersalsousedtocostalot.

However,thepastfewyearssawtheriseofanewmovement:open-sourcehardware. Asforopen-sourcesoftware,thismeanthathardwaredesignsstartedtobefreelyavailableandcustomizablebyeverybody. Andattheheartofthisopen-sourcehardwaremovement,aplatformwasbornthathadahugeimpactintheworldofelectronics:theArduinoplatform. Arduinoisaniceandfriendlyenvironmentinwhichtoeasilyprogrammicrocontrollers.

Andforme,thischangedeverythingwhenitcomestohomeautomation. Nowitispossiblefornearlyeverybodywithsomeelectronicsandprogrammingexperiencetomaketheirownhomeautomationsystems. Andthisispreciselywhatyouwilllearninthisbook.

PrefacetotheThirdEditionSincethefirstedition,thousandsofpeoplehaveusedtheprinciplespresentedheretobuildtheirownhomeautomationsystems. Ihavealsoreceivedalotofconstructivefeedbackthatallowedmetoimprovethebookandcomeupwithasecondedition.

However,alotofthesecommentsthatIreceivedonthefirsttwoeditionsofthebookalsoconcernedtherelativedifficultyoftheprojectsthatwerepresented. Itwaslessaboutthecontentoftheprojectsthemselves,andmoreaboutthenumberofprogramminglanguagesusedinsomeoftheprojects. Forexample,intheprojectsincludingcommunicationsbetweentheArduinoboardandyourcomputer,IusedacombinationofPython,PHP,HTMLandJavaScript. Youalsohadtoinstallandrunawebserveronyourcomputer,whichaddedanotherlayerofcomplexity.

Thiswhyforthisthirdeditionofthebook,Iputtheemphasisonsimplifyingthings. First,Iseparatedthebookintotwoparts. Thefirstpartisaboutbuildingself-containedhomeautomationsystems,withnolinkatallwithacomputeroranotherdevice. Therefore,theseprojectsonlyusetheArduinoprogramminglanguage.

Thesecondpartofthebookuseswhatyouwilllearninthefirstpart,byaddingwirelessmodulestothehomeautomationprojects. Andtobuildtheinterfaceonyourcomputer,Ionlyusedonelanguage:JavaScript. IcompletelyremovedtheneedforotherlanguageslikePythonorPHP.Also,IusedNode.JS,whichallowstoprograminJavaScriptontheserverside. Thisalsoeliminatestheneedtoinstallawebserveronyourcomputer.

Ihopethatyouwilllikethenewpresentationofthebook,andthatyouwillusewhatyouwilllearninthisbooktobuildevenmoreexcitinghomeautomationprojectswithArduino.

Introduction

1 HowistheBookOrganized?

Thisbookisdividedintwomainparts. Thefirstpartofthebookisdedicatedtobuildingself-containedhomeautomationsystemsthatworksontheirown. Forexample,thefirstsystemthatwearegoingtobuildisasimplealarmsystemwithamotionsensor.

Thesecondpartofthebookwillbemoreadvanced,aswearegoingtointerfacehomeautomationprojectswirelesslywithyourcomputer. Forexample,wearegoingtobuildagraphicalinterfacetocontrolalampviaWiFi.

Theentirebookisorganizedaroundprojectsonaspecifictopic,inwhichyouwilllearnaspecificsetofnewskills. Ithinkthisisdefinitelybetterthana“onefits-all”solutionwhereIwouldhavetaughtyouhowtobuildaspecifichomeautomationsystem. Withsmallerprojects,youwilllearnmuchmoreandmuchfaster,andevenmoreimportantlyyouwillhavethesetoftoolstobuildyourownsystemthatistailoredtoyourownhome.Thegoalofthisbookisreallytoinitiateyoutotheworldofhomeautomationusingopen-sourcehardwareandtoshowyouwhatispossible.

Eachchapterwillstartwithverybasicconsiderationsandprojects,andthenwewillbuildontopofthemtoarriveatmorecomplexhomeautomationprojects. Ineverychapterofthebook,youwillfindsectionsthatareorganizedasmini-projects. Inproject,youwillfindalistofwhatyouwillactuallylearnbydoingthistutorial,whathardwareyouwillneed,andastep-by-stepguideonhowtodoit,alongwithscreenshotsandpicturestoguideyoubetterthroughtheprojects.

Asanaid,therewillbelinkstowebsitesforreferencepurposes. Thesearetohelpyoufindhardwarecomponents,andnotethatIhavenocommercialcontractwiththewebsitesthatImentionintheselinks. Also,ineveryprojectIgivesomeadvicetouseequivalentcomponentstotheonesIused,incaseyoualreadyhavesomecomponentsonyourdesk.

Allchaptersincludeadetailedwalkthroughofthecodeusedtobuildthedifferentprojectsinthisbook. Inthesewalkthroughs,Idetailthemostimportantpartssothatyoucanunderstandhoweachhomeautomationprojectworks. However,becauseinsomeprojectsofthisbookthecodeisreallylong,Iwillonlygothroughthemostimportantpiecesofthecode.

Therefore,itisrecommendedthereaderalwaysrefertotheGitHubrepositoryofthisbooktogetthecompletecode. YouwillfindthelinktotheGitHubrepositoryineverychapterofthisbook,orifyouwanttohavealookrightnow,thelinkis:


Notethatallchaptersweredesignedtobecompletelyindependentfromeachother,soyoucanstartwithwhateverchapteryoulikeinthebookwithoutbeinglost. However,especiallyifyouareabeginner,itishighlyrecommendedtofollowthechaptersofthisbookinorderfromthestart.

InChapter1,youwilllearnaboutwhattheArduinoplatformreallyis,andwhyitissuchagreatopportunityforhomeautomationsystems. ThechapterwillstartwithageneralintroductiontotheArduinoplatform,andwewilldiveintothethemeofthebookwithafirsthomeautomationproject.

Afterthat,inChapter2,youwillperformyourfirstmeasurementsusingtheopen-sourcehardwareplatformArduino,andyouwilllearnhowtovisualizedataonaLCDscreen.

InChapter3,wewillcontinueourjourneyintohomeautomationsystems. WearegoingtobuildasmartlampwithArduino,thatautomaticallyswitchesonoroffaccordingtotheambientlightlevels.

Chapter4willintroducethesecondpartofthisbook,inwhichwewillbuildwirelesshomeautomationsystems. Forourfirstwirelessproject,wearegoingtobuildXBeemotionsensorsandmanagethemfromyourcomputer.

InChapter5,wearegoingtouseanotherwirelesstechnologywhichisusedinhomeautomation:Bluetooth. Wewillinterfaceatemperature&humiditysensortoArduino,andmeasuredataremotely. Wewillalsobuildaninterfaceonyourcomputertodisplaythedata.

InChapter6,IwillshowyouhowcontrolalampusingWiFi. Notonlywillyoubeabletocontrolthislampfromyourcomputer,butalsofromanydeviceconnectedtoyourlocalWiFinetwork.

Finally,inChapter7,wewillseehowtouseeverythingyouhavelearnedinthisbooktobuildasmallhomeautomationsystemcomposedofmanyelements,allcommunicatingwithacentralinterface.


2 WhyOpen-Source?

Alltheprojectsyouwillfindinsidethebook(andonthecompanionwebsite)arecompletelyopen-source,forbothhardwareandsoftware. Sowhatexactlydoesthismean? Whataretheadvantages? Andwhymakeitanessentialpartofthebook?

Well,letmefirstsayafewwordsabouttheopen-sourcehardwaremovement. Open-sourcesoftwarehasbeenaroundforquiteawhilealready,withtheLinuxoperatingsystemanditsentireecosystem,butopen-sourcehardwareismuchmorerecent. Sohowcanhardwarealsobeopen-source? Well,therearemanyopen-sourcehardwarelicenses,butitbasicallymeansthatwithanopen-sourcehardwaresystem,alltheschematicsandPCBdesignfilescanbefreelyaccessedandmodifiedbyanybody,asyouwoulddownloadandmodifyopen-sourcesoftware. Open-sourcehardwareactuallygoesfurtherthanjustopen-sourceelectronics,asitalsoconcernsopen-sourcedesignsfor3Dprintingforexample,butthisissomethingwewon’ttouchinthisbook.

Thereareseveraladvantagesofthisopen-sourceapproachforhardwaresystems. Thefirstoneisthatitallowspeopletohavealookintothehardwaresystemsthemselves,andunderstandwhythehardwaresystemtheyareusingisworkingalongwiththeopen-sourcesoftwarethatusuallycomeswithit. Butthemainadvantageformeisthatitallowspeopletomodifythehardwaresystemsandthensharethemagainwiththecommunity. Thisproducesamuchfasterdevelopmentprocessforhardwareproductsasitreallyengagestheusersandcreatescommunitiesaroundagivenhardwareproduct.

AndthisispreciselywhyIputopen-sourceatthecoreofthisbookandofthecompanionwebsite:becauseyoucanaccessthesourcesofalltheprojectsfoundinthisbook,youwillbeabletounderstandthemdeeply,modifythem,makethembetter,andthensharethemagainwiththecommunity. WhatIreallydidn’twantwastospeakabouthomeautomationbyjustpreachingmyownvision;Iwanttoengageyouasmuchaspossibletogobeyondthisbookandmakeyourownsystemswithwhatyouaregoingtolearninthebook.

3 Whatwillyoulearn?

Beforedivingintotheheartofthisbook,andbuildingyourfirsthomeautomationproject,Iwantedtospendafewmomentstoexplainwhatisyouwillactuallylearninthisbook.

Ofcourse,youwilllearnabouthomeautomation. Youwilllearnhowmostcommonhomeautomationsystemsworkbybuildingyourownsystem,forexamplesimplymeasuringthetemperatureinyourhomeanddisplayingitonyourcomputer. Youwillalsolearnaboutthebasicsofalarmsystems,andhowtocontrolthelightsinyourhomesotheycanadapttoyourcommandsortotheambientluminosity.

Butyouwilllearnmorethanthat. YouwilllearnaboutwhatIconsidertobeoneofthemostimportantplatformsatthemomentwhenitcomestodo-it-yourselfelectronicsprojects:theArduinoplatform. Whatyouwilllearnaboutthisplatformcanthenbeusedagaininmanyotherprojects.

Youwillalsolearnaboutelectronicsingeneral. Fromthemostbasicthing,likehowtoconnectamotionsensortotheArduinoboard,tohowtoconnectadigitalsensor,wewillcoveralotinthedomainofelectronics,andtheknowledgeyouwillacquirecanalsobeusedinseveraldomainsoutsideofhomeautomation.

Finally,youwillalsolearnaboutsoftwaredevelopment. WewillfirstprogramtheArduinoboardusingtheArduinoIDE,whichisbasedonC/C++. IwillalsointroduceabitofHTMLandJavascripttomakeremotemeasurementspossible,andtocontrolhomeautomationsystemsfromyourcomputer. Sowithalltheswitchingbetweenprojectsandlanguages,youwillalsoacquireasolidbackgroundinsoftwaredevelopment.

4 Safetyconcerns

Mostoftheprojectsyouwillfindinthisbookuselow-voltagedevices,whicharecompletelyharmless. However,becauseinagoodhomeautomationsystemwewanttocommandsome110or230Vdeviceslikelamps,someprojectswillmakeuseofsuchvoltagesourcesandcanbedangerousifcertainprecautionsarenottaken.

Don’tworry. Youcanlearnabouthomeautomation&Arduinoandcompletealloftheprojectsfoundinthisbookwithouteverconnectingyoursystemstothepowerpluginyourwall,butifyouactuallywanttoinstallsomeofthesedevicesinyourhomeIreallyadvisereadingthissectioncarefully.

Itisusuallyacceptedthatanythingabove50Visdangerous,and25Visusuallytakenasa“safe”value.

Forus,itmeansthatmostcircuitswillbesafe(Arduinooperatesat5Vor3.3V),theonlythingwherewewillhavetobecarefuliswhenconnectingsomepartofyourcircuittothemainselectricity(whichisat110VintheUSor230VinEurope,forexample).

Therisksofbeingindirectcontactwithavoltageabove50Vareveryhigh,andtheconsequencesincludeventricularfibrillation,cardiacarrest,respiratoryarrest,andseriousburns,allpossiblyleadingtodeath.

Itisactuallynotthatdifficulttoavoidriskswhenworkingwithhighvoltages. Thefirstone,whichseemsquiteevident,istoalwaysworkwiththecircuitbeingoff,andtobefarfromitwhenthecircuitisinoperation. Alsokeepinmindthatsomethinginsidethecircuitcouldhavebrokendownandtouchedthecaseofyourdevice,sodon’ttouchanythingwhenthecircuitisinoperation.

Alsomakesurethatthecircuitisde-energizedbeforetouchingit. Indeed,somehigh-voltagecircuitscancontaincomponentslikecapacitorsthatstoreenergyevenifthepowerhasbeenshutdown. However,youwon’tfindsuchcircuitsinthisbook.

5 Prerequisites

Firstofall,youcouldjustreadthisbookfromstarttofinishwithoutactuallydoinganyoftheprojects,andstilllearnalotaboutelectronics,programmingandofcoursehomeautomation. However,Ireallyrecommendspendingtimedoingtheprojectsyourself. Youwilllearnsomuchmorebydoingso.

Nowfortheprerequisites. Youactuallydonotneedtoknowmuch,butapreviousexperiencewiththeworldofelectronicsandprogrammingwillbeusefulandwillallowyoutogetthroughtheprojectsfaster. Theprojectscanberunfromanycomputer,butIwillfocusonusingtheOSXandLinuxoperatingsystems. However,theArduinosoftwarealsoperfectlyrunsonWindowsandalltutorialswillworkunderthisoperatingsystem.

Fortheprogrammingside,IwilluselanguageslikeC/C++,HTML,andJavascript. IwillnotmakeafullintroductionoftheselanguageswhenIusethem,butIwilldetaileveryoneofthefunctionsIuseandpointtoareferenceifIamusingmorecomplexfunctionsinoneoftheselanguages. Butoverall,wewillkeepitsimple.

Fortheelectronicspart,Iwillintroducethefunctionofeverynewcomponent. Also,foreverycomponentusedintheprojectsinthisbook,Iwillincludeusefullinksinthesupportpagessothatyoucaneasilyfindandbuythesecomponentsontheweb. Alloftheprojectswilluseabreadboardforrapidprototypingsoyoudon’thavetosolderanything.Again,thegoalofthisbookistoteachyouabouthomeautomationusingtheArduinoplatformsoyoucanbuildyourownsystemslater.

Mostofthehardwareandthesoftwarerequiredforthisbookarespecifictoeverychapter.However,thereareafewthingsyouwillneedthroughoutthebookandthosewewillinstallrightnow.

ThefirstthingistheArduinoIDE(IDEmeanIntegratedDevelopmentEnvironment). YoucangrabitontheofficialArduinowebsiteatthefollowingaddress:

http://arduino.cc/en/Main/Software

Inthesecondpartofthebook,wearegoingtoconnectourprojectswirelesslytoyourcomputer. Tousetheserver-sidecode,youaregoingtoneedtohaveNode.jsinstalledonyourcomputer. Node.jsissoftwarethatallowstheconstructionofserver-sidecodeusingJavascript,andwewilluseittobuildinterfacesforourhomeautomationprojects. You

http://arduino.cc/en/Main/Software

cangrabitatthefollowingaddress:

http://nodejs.org/download/

Itisalsoavailableforallplatforms,andeasytoinstall. ToinstallitunderWindowsorOSX,simplydownloadtheinstallerfile,andfollowtheinstructionsgivenbytheinstallsoftware.

IfyouareunderWindows,inorderforNode.jstoworkcorrectlyyoualsoneedtocreateafoldercallednpminsidethisfolder:

C:\Users\yourUserName\AppData\Roaming\

IfyouarerunningunderUbuntuorotherLinuxdistributions,youhavetheenterthefollowingcommandsinaterminal:

sudoapt-getinstallpython-software-properties

sudoapt-add-repositoryppa:chris-lea/node.js

sudoapt-getupdate

Then,enterthefollowingcommandtoinstallNode.js:

sudoapt-getinstallnodejs

NotethatunderLinux,Node.jsissometimesdenotedasnodejsandnotnodelikefortheotheroperatingsystems.

IfyouareusingaRaspberryPi,firstenterthiscommandinaterminal:

sudowgethttp://node-arm.herokuapp.com/node_latest_armhf.deb

Then,installNode.jsbytyping:

sudodpkg-inode_latest_armhf.deb

http://nodejs.org/download/

Chapter1

GettingStarted

1.1 TheArduinoPlatform

Youarejustminutesawayfromactuallydoingyourfirstopenhomeautomationproject.Beforethat,however,Iwanttointroducetheplatformthatwewillbeusinginthiswholebook:theArduino.

ThehistoryofArduinobeganin2005,whenthefoundersMassimoBanziandDavidCuartielleswantedtomakeadevicethatwouldbeeasytoprogrambynon-experts,sothattheirstudentsindesigncouldbuildprojectsthatusedmicrocontrollers. TheArduinoplatformwascreatedtobenotonlyabouttheboardsandthemicrocontrollers,butalsoasacompletehardwareandsoftwareecosystemthatmadethelifeoftheusermuchsimplercomparedtoothermicrocontrollersolutions.

Onthehardwareside,Arduinoisasingle-boardmicrocontrollersystem,usuallyequippedwithan8-bitAtmelAVRmicrocontroller,althoughnewmodelsliketheArduinoDuehavea32-bitARMprocessor. Forourprojects,wedon’tneedthatmuchpower,andwewillonlyusethemostcommonArduinoboard:theArduinoUno.

OnecharacteristicofArduinoboardsisthattheirpinsarealwaysexposedinasimilarfashion,whichmeansthatitisveryeasytopluginextensions,calledshields,directlyintotheboards. Theseshieldscanaddvariousfunctionalitiestotheboard,liketheabilitytocontrolDCmotorsforroboticsapplications,ortoconnectwirelesslytoyourphoneviaBluetooth.

Butforme,it’sreallythesoftwarepartthatmakestheArduinoplatformsopowerful. ToprogramanArduinoboard,youcanusetheofficialArduinosoftware(whichistotallyfreetodownload)andthenusealanguageclosetoC++toactuallywritethecodethatyouwilluploadtotheboard. Comparedtoothermicrocontrollers,believeme,itisveryeasytoprogramtheboardtomakeitdowhatwewant. Forexample,asimpleinstructionlikemakinganLEDlightuponlytakesasinglelineofcodewithanArduinoboard,whereasitwouldtakemanylineswithothermicrocontrollers.

AnotherimportantpointisthatthereisalsoahugecommunityaroundtheArduinoplatform. ThismeansthateveryfunctionuseisreallywelldocumentedontheofficialArduinowebsite(www.arduino.cc). Youwillalsofindtutorialsformostofthecommonlyusedfunctionsoftheboard.

Iwillnowgiveyouabitmoredetailabouttheboardthatwewillbeusinginthisbook:theArduinoUno. HereisapictureoftheboardIpersonallyusedforalltheprojectsin

thisbook:

Theboarditselfisverytiny. WhatyoucanseeonthelowerrightportionofthepictureisanAtmelmicrocontroller,the“brain”oftheboard. Itreceivesthesoftwarewhichwewilldevelopforourhomeautomationprojects. Onthetopandonthebottomoftheboard,youwillseetworowsofconnectors. Wewillusethesetoconnecttheinputandoutputsignalssuchastheanaloginputs,thedigitalinputsandoutputs,andreferencevoltageslikethegroundand5V.Finally,youcanseetheUSBconnectorontheleftuppercorner. Thiswillconnecttheboardtothehostcomputer.

1.2 WhatyouNeedtoKnowAboutElectronics

Thisisnotabookaboutgeneralelectronics;therearemuchbetterbooksforthat. Thisbookwillteachyouhowtobuildhomeautomationsystems. Itwillcoachyouhowtoconnectdifferentcomponents,sensorsandotherdevicestotheArduinoplatform.

However,inordertounderstandhowthesecomponentswork,youneedtounderstandseveralbasicelectronicprinciples. Thissectionwillgiveyouaquickintroductionoftheprinciplesusedintheprojectsfoundinthisbook.

Mainvariablesusedinelectronics

Tocharacterizeacircuit,manyvariablesareused,butwearejustgoingtolookatthemostimportantones.

ImaginethatanelectricalcircuitislikewaterflowingfrompointAtopointB.Forwatertoflownaturallyintothecircuit,weneedadifferenceofheightbetweenAandB.Andinelectricalcircuits,thisdifferenceiscalledthevoltage,usuallynotedasV.

WecanalsodefinetheequivalentflowofwaterbetweenAandBastheflowofelectrons,whichisthecaseinanelectricalcircuit. ThiselectronflowiscalledtheelectricalcurrentandwillberepresentedbytheletterI.

WecanalsoexpressthepowerPdissipatedbyagivencomponent,inWatts,bymultiplyingthevoltagebythecurrent:P=V*I.

Basiccircuitrepresentation

Inordertorepresentelectricalcircuits,anormalizedsetofsymbolsisused. Here,forexample,isasimplecircuitwithavoltagesourceVCC,aresistorR1,anLEDcalledLED1,andagroundGND.

Lateron,wewillseemoredetailsaboutsomeofthesecomponents,butfornow,let’sjustidentifythecomponentswhichareusuallyfoundinmanycircuits.

Whenreadingacircuit,youshouldfirstlocatethepowerandgroundpins. Here,thepowerisrepresentedbytheVCCpin,whichwillusuallybeequalto5Vintheprojectsfoundinthisbook. ThegroundpinhereisrepresentedbyGND.

AfterVCCandGND,youcanlookforthecomponents. Here,wesimplyhavearesistorandanLED.

Powersources

Inthefirstcircuitofthissection,thepowersourcewasapinnamed“VCC”. Thissourcecanbeliterallyanything,butbyconvention,VCCwilldenoteapositive,low-voltagepowersource(usually3.3,5or12V).

Topowertheprojectsthatyouwillfindinthisbook,theUSBportoftheArduinoboardwillusuallybeused. However,youcanalsopowerupyourArduinoboardfromotherpowersourceslikeregulatedpowersupplieswhichcanbedirectlypluggedintothewallsocket(bewarenottoexceedthemaximumvoltageacceptedbyyourArduinoboard)orontobatteries.

Resistors

Resistorsarekeycomponentsofmostelectricalcircuits. Takingagainourpreviousanalogywithwater,aresistorwillactuallylimittheflowofwater(orelectrons)inagivenbranchofthecircuit.

Toquantifyhowmuchtheresistorislimitingthecurrentinacircuit,wecanintroduceanewvariablecalledR,resistancewhichismeasuredinOhms. Foraresistor,theformulathatlinksvoltage,currentandresistanceiscalledOhm’slaw:V=R*I.

LEDs

LEDs,shortforLightEmittingDiodes,arethemostcommonlyusedcomponentsforsignalingandtestinginacircuit. Whencurrent(usuallyabout20mA)isgoingthroughanLED,theyemitlight,whichcanbered,blue,greenorevenwhite,dependingontheLED.

OntheArduinoboardforexample,LEDsareusedtomakesuretheboardison,toindicatethataserialcommunicationisactuallyhappeningorasatestcomponentforsoftware(onpinnumber13).

Asshowninthefirstcircuitofthissection,LEDsareusuallyassociatedwithresistorstolimitthecurrentthatflowsthroughthem. Beware,thepinsofanLEDarenotequal–thepositivepowersupply(forexample,VCC)hastogoontheleftsideoftheLEDcalledtheanode,andtheotherpin,calledthecathode,hastobeconnectedtotheground. Youcaneasilyidentifythecathodeasittheonewiththeshorterlead.

Relays

Inhomeautomation,wewanttoswitchthingslikelampsonandoffasyouwoulddowhenyoupressalightswitchonthewall. Thisisdoneusingrelays,whichbasicallyareelectromechanicalswitches.

Therearetwoprimarypartsinarelay. Theleftpartofthesymbolisthecoil,andisthe“control”partoftherelay. Whenavoltage(usually5Vforrelaysusedinthisbook)isappliedtothecoil,theotherpartoftherelaywillswitchitsstate,goingfromaclosedstatetoanopenstate,forexample.

Thecoolthingisthatthissecondpartoftherelaycanhandlemuchhighervoltages(upto300Vfortheonesusedinthisbook)comparedtowhattheArduinoboardcouldhandle.ThisallowsanArduinoboardtocontroldevicesthatusepowerdirectlyfromthemainselectricity,likelamps.

Goingfurther

Thissectionisclearlyjustanintroductiontoelectronicsandtothecomponentsthatwearegoingtousethemostinthisbook.

Togofurtherandlearnmoreaboutelectronics,thereareseveralthingsthatyoucando.

Ofcourse,justbrowsingtheInternetisanoption. Youwillfindmanyresourcesbyusingthisway. YoucanalsohavealookinsidetheResourceschapterofthisbooktofindseveralbookrecommendationsaboutArduino&electronics.

1.3 YourVeryFirstProject:aSimpleAlarmSystem

Toendthischapter,wearegoingtobuildourveryfirsthomeautomationproject:asimplealarmsystem. WearegoingtointerfaceaPIRmotionsensorwithArduino. Ifmotionisdetected,wewillflashanLEDandmakesomesoundwithasmallpiezobuzzer. ThissimpleprojectwillgiveyouthebasicsofhomeautomationwithArduino.

Hereisthelistofcomponentsyouwillneedforthisproject:

ArduinoUno(http://www.adafruit.com/product/50)PIRmotionsensor(http://www.adafruit.com/product/189)LED(https://www.sparkfun.com/products/9590)330Ohmresistor(https://www.sparkfun.com/products/8377)Piezobuzzer(http://www.adafruit.com/product/160)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

Wecannowstartassemblingtheproject. Tohelpyouout,theschematicbelowsummarizesthehardwareconnections:

ThisimagewascreatedwithFritzing(http://fritzing.org/).

http://www.adafruit.com/product/50


https://www.sparkfun.com/products/9590





http://fritzing.org/

First,placeallthecomponentsonthebreadboard. Afterthat,positionthebreadboardnexttotheArduinoboard. Then,connectthePIRmotionsensortothebreadboard. ConnecttheGNDpinoftheArduinoboardtothebluerailofthebreadboardaswewillneedtoconnectalldevicestothesameground.

FortheLED,connecttheresistorinserieswiththeLEDanodeonthebreadboard(theanodeisthelongestpinontheLED). Then,connecttheotherpinoftheresistortoArduinopin5. TheothersideoftheLEDmustbeconnectedtotheArduinoground.

ForthePIRmotionsensor,connecttheGNDpintotheArduinoground,VCCtotheArduino5Vpin,andSIGpintoArduinopin7.

ForthePiezobuzzer,connectthepositivepin(markedwitha+)toArduinopin8,andtheotherpintotheArduinoground.

Thisisapictureofthefullyassembledproject:

Nowthatthehardwareisassembled,wecanstartwritingtheArduinosketchforoursimplealarmsystem. Thisisthecompletecodeforthispart:

//Codeforthesimplealarmsystem

//Pins

constintalarm_pin=8;

constintled_pin=5;

constintmotion_pin=7;

//Alarm

booleanalarm_mode=false;

//VariablesfortheflashingLDED

intledState=LOW;

longpreviousMillis=0;

longinterval=100;//Intervalatwhichtoblink(milliseconds)

voidsetup()

{

//Setpinstooutput

pinMode(led_pin,OUTPUT);

pinMode(alarm_pin,OUTPUT);

//Waitbeforestartingthealarm

delay(5000);

}

voidloop()

{

//Motiondetected?

if(digitalRead(motion_pin)){

alarm_mode=true;

}

//Ifalarmmodeison,flashtheLEDandmakethealarmring

if(alarm_mode){

unsignedlongcurrentMillis=millis();

if(currentMillis-previousMillis>interval){

previousMillis=currentMillis;

if(ledState==LOW)

ledState=HIGH;

else

ledState=LOW;

//SwitchtheLED

digitalWrite(led_pin,ledState);

}

tone(alarm_pin,1000);

}

}

Let’snowseethedetailsofthiscode. Itstartsbydeclaringthepinstowhichthedifferentcomponentsareconnectedto:

constintalarm_pin=8;

constintled_pin=5;

constintmotion_pin=7;

Wewillstorethefactthatthealarmisonornotinsideavariable:

booleanalarm_mode=false;

WewillalsohaveavariabletomaketheLEDflashwhenthealarmison:

intledState=LOW;

longpreviousMillis=0;

longinterval=100;//Intervalatwhichtoblink(milliseconds)

Now,insidethesetup()functionofthesketch,weneedtosetthepinsfortheLEDandthePiezoasoutputs:

pinMode(led_pin,OUTPUT);

pinMode(alarm_pin,OUTPUT);

Wealsowaitfor5seconds,sothealarmdoesn’tturnonrightaway:

delay(5000);

Intheloop()functionofthesketch,wecontinuouslycheckthestateofthePIRmotionsensor. Ifsomemotionhasbeendetected,wesetthealarmvariabletotrue:

if(digitalRead(motion_pin)){

alarm_mode=true;

}

Now,ifthealarmison,wedotwothings:continuouslyflashtheLEDandinitiatethePiezobuzzertomakesomenoise. Thisisdonebythefollowingpieceofcode:

if(alarm_mode){

unsignedlongcurrentMillis=millis();

if(currentMillis-previousMillis>interval){

previousMillis=currentMillis;

if(ledState==LOW)

ledState=HIGH;

else

ledState=LOW;

//SwitchtheLED

digitalWrite(led_pin,ledState);

}

tone(alarm_pin,1000);

}

NotethatallthecodesforthisfirstprojectcanbefoundontheGitHubrepositoryofthebook:

https://github.com/openhomeautomation/home-automation-arduino/

Youcannowtestthisfirstprojectofthebook. UploadthecodetotheArduinoboardusingtheArduinoIDE.Trywavingyourhandinfrontofthesensoraftertheinitial5secondsdelayhaspassed. YoushouldhearthealarmturnonandseetheLEDflashingcontinuously. Toturnitoffagain,simplypresstheredresetbuttonontheArduinoboard.

Incaseitisnotworkingatthispoint,thereareseveralthingswhichyoucancheck. First,makesurethatallthehardwareconnectionsarecorrectbydoingthehardwareconfigurationpartagain. Also,makesurethatyouhavecorrectlyuploadedthelatestversionofthecodethatyoucanfindinsidetheGitHubrepositoryofthebook.

IhopethissimpleprojectgaveyouanideaofwhatyoucandowithArduinoforhomeautomationapplications. Inthenextchapterofthebook,wearegoingtousetheArduinoplatformtobuildevenmoreexcitinghomeautomationapplications!

https://github.com/openhomeautomation/home-automation-arduino/

Chapter2

BuildingaWeatherMeasurementStationInthepreviouschapter,whichreallyintroducedyoutotheworldofopen-sourcehomeautomation,youlearnedhowtointerfaceamotionsensorwithArduinotocreateasimplealarmsystem.

Inthisproject,Iwillshowyouhowtomonitorthetemperature,humidityandlightlevelofaroomusingArduino,atemperature&humiditysensor,aphotocell,andaLCDscreen. WearegoingtocontinuouslydisplayallthisdataontheLCDscreen.

Thisprojectperfectlyrespectsthefoundationsofthisbookasitusesonlyopen-sourcecomponents. Youcanseeitasthefoundationofamorecomplexsystemtoremotelymonitorinformationaboutyourhome.

2.1 Hardware&SoftwareRequirements

Forthisproject,youwill,ofcourse,needanArduinoUnoboard. YoucanalsouseotherArduinoboardslikeanArduinoMegaorLeonardoastheywillworkjustfinetoo.

Fortemperatureandhumiditymeasurements,youwillalsoneedaDHT11sensor,alongwitha4.7Kresistor. YoucanalsouseaDHT22sensorwhichismoreprecise,onlyyouwillhavetochangeonelineofcode.

Forlightlevelsmeasurements,Iusedaphotocellwitha10KOhmresistor. Thiswillreturnasignalwhichisproportionaltotheincominglightlevel.

YouwillalsoneedanLCDscreentodisplaythemeasurements. Iuseda4x20characterLCDsoIcandisplayuptofourdifferentmeasurementsatthesametime. Youcan,ofcourse,useasmallerLCDscreen,butyouwillonlybeabletodisplaythetemperatureandhumidityatthesametime,forexample.

ThescreenIusedforthisprojectusesanI2CinterfacetocommunicatewiththeArduinoboard. IstronglyrecommendusingascreenwiththisinterfaceasthereareonlytwodatapinsneededtoconnecttotheArduinoboard.

Finally,Iusedabreadboardandsomemale-malejumperwirestomakethedifferentelectricalconnections.

Hereisalistofallcomponentsusedinthisprojectalongwithlinkswhereyoucouldpurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)DHT11sensor+4.7kOhmresistor(http://www.adafruit.com/product/386)Photocell(http://www.adafruit.com/product/161)10kOhmresistor(https://www.sparkfun.com/products/8374)LCDdisplay(http://www.robotshop.com/en/dfrobot-i2c-twi-lcd-module.html)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

YouwillalsoneedthelibraryfortheDHTsensor:

https://github.com/adafruit/DHT-sensor-library

AndtheLiquidCrystallibraryfortheLCDscreen:





http://www.robotshop.com/en/dfrobot-i2c-twi-lcd-module.html




https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads

Toinstallalibrary,simplyputthefolderinthe/libraries/folderofyourmainArduinofolder.


2.2 HardwareConfiguration

Thehardwareconnectionsforthisprojectarequitesimple:wehavetoconnecttheDHT11sensor,theLCDscreenandthepartresponsibleforthelightlevelmeasurementwiththephotocell. Tohelpyouout,thefollowingpicturesummarizesthehardwareconnections:


First,connecttheArduinoUno+5Vpintotheredrailonthebreadboard,andthegroundpintothebluerail.

ToknowwhichpintoconnectfortheDHT11sensor,refertothepicturebelow:


Then,connectpinnumber1oftheDHT11sensor(VCC)totheredrailonthebreadboard,andpinnumber4(GND)thebluerail. Also,connectpinnumber2ofthesensortopinnumber7oftheArduinoboard. TofinishupwiththeDHT11sensor,connectthe4.7kOhmbetweenpinnumber1and2ofthesensor.

Forthephotocell,placethecellinserieswiththe10kOhmresistoronthebreadboardfirst. Next,connecttheotherendofthephotocelltotheredrailonthebreadboard,andtheotherendoftheresistortothebluerail(ground). Finally,connectthecommonpinbetweenthephotocellandtheresistortotheArduinoUnoanalogpinA0.

Now,wearegoingtoconnecttheLCDscreen. SinceweareusinganLCDwithanI2Cinterface,therewillonlybetwowiresneededtoconnectforthesignal,andtwoforthepower. ConnecttheLCDpincalledVCCtotheredrailonthebreadboard,andtheGNDpintothebluerailonthebreadboard. Then,connecttheLCDpinSDAtotheArduinopinA4,andtheSCLpintotheArduinopinA5.

Hereisapictureofthefullyassembledprojectsoyoucanhaveanideaonhowthecompleteprojectlookslike:

2.3 TestingtheSensors

Nowthatthehardwareoftheprojectisfullyassembled,wearegoingtotestthedifferentsensorsontheboard. Todoso,wearegoingtowriteasimpleArduinosketch. WewillsimplyreadoutdatafromthesensorsandprintthesedataontheSerialport. Thisisthecompletecodeforthispart:

//CodetomeasuredataandprintitontheSerialmonitor

//Libraries

#include"DHT.h"

//DHTsensor

#defineDHTPIN7

#defineDHTTYPEDHT11

//DHTinstance

DHTdht(DHTPIN,DHTTYPE);

voidsetup()

{

//InitializetheSerialport

Serial.begin(9600);

//InitDHT

dht.begin();

}

voidloop()

{

//MeasurefromDHT

floattemperature=dht.readTemperature();

floathumidity=dht.readHumidity();

//Measurelightlevel

floatsensor_reading=analogRead(A0);

floatlight=sensor_reading/1024*100;

//Displaytemperature

Serial.print("Temperature:");

Serial.print((int)temperature);

Serial.println("C");

//Displayhumidity

Serial.print("Humidity:");

Serial.print(humidity);

Serial.println("%");

//Displaylightlevel

Serial.print("Light:");

Serial.print(light);


Serial.println("");

//Wait500ms

delay(500);

}

ItstartsbyimportingthelibraryfortheDHTsensor:

#include"DHT.h"

AndcreateaDHTinstance:


Inthesetup()functionofthesketch,wehavetoinitializethesensor:

dht.begin();

AndtheSerialport:

Serial.begin(9600);

Intheloop()function,wearegoingtocontinuouslyreaddatafromthesensorsandprintthemtotheSerialport. Westartbygettingdatafromthetemperatureandhumiditysensor:



Forthephotocell,wefirstreaddatafromtheanalogpinA0,whichreturnsavaluefrom0to1023astheresolutionoftheAnalog-To-DigitalconverteroftheArduinoUnoboardis10bitsor1024values. Then,wedividethisvalueby1024andmultiplyitby100tohavethelightlevelasapercentage:



Next,weprintthesedifferentmeasurementstotheSerialport. First,thetemperature:

Serial.print("Temperature:");

Serial.print((int)temperature);

Serial.println("C");

Printinghumidityissimilartothelightlevel:

Serial.print("Light:");

Serial.print(light);


Finally,weintroduceadelayof500msbetweeneachnewsetofmeasurements:

delay(500);

NotethatthecompletecodeforthischaptercanbefoundonthecorrespondingfolderinsidetheGitHubrepositoryofthebook:


It’snowtimetotestthisfirstArduinosketch. UploadthecodetotheArduinoboardand


opentheSerialmonitorinsidetheArduinoIDE(makingsuretheSerialspeedissetto9600). Thisiswhatyoushouldsee:

Temperature:25C

Humidity:36.00%

Light:83.79%

Ifthatworks,congratulations,yoursensorsareworkingcorrectly! Youcantry,forexample,topassyourhandinfrontofthephotocell,andyoushouldseethatthelightlevelchangesinstantly.

Incaseitisnotworkingatthispoint,thereareseveralthingsthatyoucancheck. First,makesurethatthesensorsandtheLCDscreenarecorrectlyconnectedtotheArduinoboard. Also,makesurethatyouhavecorrectlydownloadedandinstalledthelibrariesfortheDHTsensorandtheLCDscreen.

2.4 DisplayingtheDataontheLCDScreen

Wearenowgoingtoputthingstogether,andusewhatwealreadydidtofinishourproject. Wewillthereforekeepthemeasurementpartofthesketchwejustwrote,anddisplaytheresultsontheLCDscreen.

Asmostofthecodeisthesamecomparedtotheprevioussketch,IwillonlydetailthepartsthatwereaddedforthedisplayontheLCDscreen. Ofcourse,youcanfindallthecodeontheGitHubrepositoryofthebook. Thisisthecompletecodeforthispart:

//Codetomeasuredata&displayitontheLCDscreen

//Libraries

#include<Wire.h>

#include<LiquidCrystal_I2C.h>

#include"DHT.h"

//DHTsensor

#defineDHTPIN7

#defineDHTTYPEDHT11

//LCDdisplayinstance

LiquidCrystal_I2Clcd(0x27,20,4);

//DHTinstance


voidsetup()

{

//Initializethelcd

lcd.init();

//PrintamessagetotheLCD.

lcd.backlight();

lcd.setCursor(1,0);

lcd.print("Hello!");

lcd.setCursor(1,1);

lcd.print("Initializing…");

//InitDHT

dht.begin();

//ClearLCD

delay(2000);

lcd.clear();

}

voidloop()

{

//MeasurefromDHT



//Measurelightlevel




lcd.setCursor(1,0);

lcd.print("Temperature:");

lcd.print((int)temperature);

lcd.print((char)223);

lcd.print("C");

//Displayhumidity

lcd.setCursor(1,1);

lcd.print("Humidity:");

lcd.print(humidity);

lcd.print("%");

//Displaylightlevel

lcd.setCursor(1,2);

lcd.print("Light:");

lcd.print(light);

lcd.print("%");

//Wait100ms

delay(100);

}

ItstartsbyincludingtherequiredlibrariesfortheLCDscreenandtheDHTsensor:

#include<Wire.h>


#include"DHT.h"

Then,wecancreatetheinstanceoftheLCDscreen. Ifyouareusingotherscreensizes,forexampleswithtwolinesonly,thisisthetimetochangeit:


Inthesetup()functionofthesketch,weneedtoinitializetheLCDscreen:

lcd.init();

Stillinthisfunction,weputthebacklightoftheLCDon,andprintawelcomemessage:

lcd.backlight();

lcd.setCursor(1,0);


lcd.setCursor(1,1);


Aftertwoseconds,wesimplycleardownthescreenbeforedoingmeasurements:

delay(2000);

lcd.clear();

Now,intheloop()functionofthesketch,afterthedifferentmeasurements,weprintoutthetemperatureonthefirstlineoftheLCDscreen:

lcd.setCursor(1,0);




lcd.print("C");

Wethenprintthehumidityonthesecondline:

lcd.setCursor(1,1);



lcd.print("%");

Now,ifyouhaveathirdlineavailable,likeonthescreenIused,youcandirectlyprintthelightlevelaswellonthethirdline:

lcd.setCursor(1,2);


lcd.print(light);

lcd.print("%");

Ifyoudon’thaveathirdlineavailableonyourLCDscreen,youhaveseveraloptions. Forexample,youcanjustintroducesomedelay,clearthescreenagain,andprintoutthelightlevelonthefirstline.

Wealsointroducea100msdelaybetweeneachsetofmeasurementsandrefreshoftheLCDscreen:

delay(100);

NotethatthecompletecodeforthischaptercanbefoundinsidetheGitHubrepositoryofthebook:


It’snowtimetotesttheproject. UploadthecodeagaintoyourArduinoboardandwaitforsometime. YoushouldbeabletoseetheLCDprintingthewelcomemessagebeforemovingontodisplaythemeasurements. Hereisapictureoftheprojectinaction:


Ifitdoesn’twork,thereareseveralthingsthatyoucancheck. Thefirstonetocheckisthatthecodetotestthedifferentsensorsisworkingcorrectly. So,donothesitatetogobacktotheprevioussectionsifnecessary. Also,makesurethatyourLCDscreeniscorrectlywired. Finally,makesurethatyouareusingthecorrectLCDlibraryforthescreenyouareusing.

2.5 HowtoGoFurther

Inthischapter,webuiltasimplehomeautomationproject:anLCDweatherstationbasedonArduino. WeinterfacedseveralsensorswithArduinolikedigitalhumidityandtemperaturesensors. Then,wedisplayedthesedataonanLCDscreen,whichisalsocontrolledbytheArduinoboard.

Thereareseveralwaystousewhatyouhavelearnedinthischaptertobuildevenmoreexcitingprojects. YoucanconnectmoresensorstotheprojectsanddisplaytheirmeasurementsontheLCDscreen. Forexample,youcanconnectabarometricpressuresensortotheproject. YoucanalsokeepthesamesensorsandgraphicallydisplaytheirmeasureddataonanOLEDscreen.

Chapter3

BuildingaSmartLampInthisproject,wearegoingtobuildaverycommonhomeautomationsystem:asmartlamp. Andbysmart,Imeanalampthatautomaticallyswitchesonwhentheambientlightlevelislow,andswitchesoffagainwhenthelightlevelrises. Todoso,wewillusearelaymoduletocontrolthelamp,andaphotocelltomeasuretheambientlightlevel.SincewewillusetheArduinoplatformtodoso,wearegoingtointroducesomeextrafeatures.

First,wewilladdacurrentsensortotheproject,sowecanknowhowmuchcurrentandenergythelampisconsumingatagivenmoment. WewillalsoaddanLCDscreentotheproject,soyoucaninstantlycheckthestateoftherelay,theenergyconsumptionofthelamp,andthevalueoftheambientlightlevel. Asforthelampitself,wearesimplygoingtouseasimpledesklamp,however,theprinciplesofthisprojectshouldworkwithanylamp.


Forthisproject,youwill,ofcourse,needanArduinoUnoorasimilarboard.

Fortherelaymodule,Iuseda5VrelaymodulefromPololu,whichnicelyintegratesarelayonaboard,alongwithalltherequiredcomponentstotheArduinoboard. HereisapictureoftherelaymoduleIused:

Tomeasurethecurrentflowingthroughthelamp,IusedaboardbasedontheAC712sensorfromITeadStudio. ThissensorisreallyeasytousewithArduino,asitreturnsavoltagethatisproportionaltothemeasuredcurrent. Withthecorrectformula,wewilltheninferthecurrentflowingthroughthelampfromthevoltagemeasuredbytheArduinoboard. Ofcourse,youcanuseotherboardsbasedonthesamesensor. Hereisapictureofthecurrent-measuringboardIusedforthisproject:


YouwillalsoneedanLCDscreentodisplaythestateoftherelay,thepowerconsumptionofthedevice,andthelightlevel. Iuseda4x20charactersLCDsothatIcandisplayuptofourlinesatthesametime. Youcan,ofcourse,useasmallerLCDscreen,butyouwillonlybeabletodisplaythestateoftherelayandthecurrentconsumptionatthesametime,forexample.

ThescreenIusedforthisprojectusesanI2CinterfacetocommunicatewiththeArduinoboard. IrecommendusingascreenwiththisinterfaceasthereareonlytwodatapinsneededtoconnecttotheArduinoboard.

Toconnectthelamptotheproject,Iusedastandardpairofpowerplugswithbarecablesattheend,withonefemalesocket(toplugthelampin)andonemalesocket(toplugitintothepowersocketinthewall). HereisapictureofthecablesIused:

Becarefulinworkingonthecablesasthisisahigh-voltageproject.

Finally,Iusedabreadboardandsomejumperwirestomakethedifferentelectricalconnections.

Hereisalistofallcomponentsusedinthisproject,alongwiththelinkswhereyoucanpurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)Relaymodule(http://www.pololu.com/product/2480)Currentsensor(http://imall.iteadstudio.com/im120710011.html)Photocell(http://www.adafruit.com/product/161)10kOhmresistor(https://www.sparkfun.com/products/8374)LCDdisplay(http://www.robotshop.com/en/dfrobot-i2c-twi-lcd-module.html)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

Forthelampitself,Iusedastandarddesklamp(30W)forthisproject.*However,therelaymoduleIusedcansupportupto1200W,soyoucanpluginmorepowerfullampsordevicesifyouwish.

Onthesoftwareside,allyouneedistheArduinoIDE,andtheLiquidCrystallibraryfortheLCDscreen:



http://www.pololu.com/product/2480

http://imall.iteadstudio.com/im120710011.html







Toinstallalibrary,simplyputthefolderinyour/libraries/folderofyourmainArduinofolder.

*Note:InUSAandCanadawhere110VACisused,standardwattageis60W.

3.2 HardwareConfiguration

Let’snowassemblethehardwareforthisproject. Wewilldosointwoparts. WewillfirstconnectthedifferentcomponentsliketherelaymoduletotheArduinoboard,andthenwewillconnectthelamptotheproject.

Thehardwareconnectionsforthefirstpartareactuallyquitesimple:wehavetoconnecttherelaymodule,thecurrentsensorandthephotocell. First,connecttheArduinoUno+5Vpintotheredrailonthebreadboard,andthegroundpintothebluerail.

Forthephotocell,placethecellinserieswiththe10kOhmresistoronthebreadboardfirst. Then,connecttheotherendofthephotocelltotheredrailonthebreadboard,andtheotherendoftheresistortothebluerail(ground). Finally,connectthecommonpinbetweenthephotocellandtheresistortotheArduinoUnoanalogpinA0.

Fortherelaymodule,therearethreepinsyouneedtoconnect:VCC,GNDandasignalpin,usuallydenotedasSIG.VCCneedstogototheArduino5Vpin,soconnectittotheredpowerrail. GNDgoestotheArduinogroundpin,soconnectittothebluepowerrail.Finally,connecttheSIGpintopinnumber8oftheArduinoboard.

Inasimilarway,connectthecurrentsensormodule. Ithasthreepins:VCC,GND,andOUT.Asfortherelay,VCCneedstogototheArduino5Vpin,soconnectittotheredpowerrail. GNDgoestotheArduinogroundpin,soconnectittothebluepowerrail.Then,connecttheOUTpintotheanalogpinA1oftheArduinoboard.

Now,wearegoingtoconnecttheLCDscreen. SinceweareusinganLCDwithanI2Cinterface,therewillonlybetwowirestoconnectforthesignal,andtwoforthepower.ConnecttheLCDpincalledVCCtotheredrailonthebreadboard,andtheGNDpintothebluerailonthebreadboard. Then,connecttheLCDpinSDAtotheArduinopinA4,andtheSCLpintoArduinopinA5.

Hereisapictureofthefullyassembledproject,withoutthelampconnectedyet:

Wearenowgoingtoconnectthelamptothehardwarewealreadyassembled. Basically,theideaistohavethemainpowersupply(comingfromthepowersocketinthewall)gototherelay,thentothecurrentsensor,andfinallytothelamp. Followthisschematictomaketherequiredconnections:

Asitimpliesdangerousvoltagelevels(110vor230vdependingonwhereyouareintheworld),youshouldtakesomeprecautionsatthispoint. Youcanfindthemintheintroductionofthisbook. Notethatyoucantestthisprojectwithouthavinganydeviceconnectedtotherelay&thecurrentsensor.

3.3 TestingtheRelay

Itisnowtimetotesttheproject. Asthemostimportantpartoftheprojectistherelaycontrollingthelamp,wearegoingtotestthere. Wearesimplygoingtoswitchtherelayonandoffcontinuouslyevery5secondsjusttocheckthattherelayisworkingandthattheconnectionswiththelampwerecorrectlymade. Hereisthecompletecodeforthispart:

//Simplesketchtotesttherelay

//Relaypin

constintrelay_pin=8;

voidsetup(){

pinMode(relay_pin,OUTPUT);

}

voidloop(){

//Activaterelay

digitalWrite(relay_pin,HIGH);

//Waitfor5seconds

delay(5000);

//Deactivaterelay

digitalWrite(relay_pin,LOW);

//Waitfor5seconds

delay(5000);

}

Itstartsbydeclaringonwhichpintherelayisconnectedto:


Inthesetup()functionofthesketch,wesetthispinasanoutput:


Then,intheloop()functionofthesketch,wesetthispintoaHIGHstate,switchingontherelay:


Waitfor5seconds:

delay(5000);

Wethenswitchtherelayoffagain:


Andwaitfor5secondsbeforerepeatingtheloop():

delay(5000);



It’snowtimetotestthesketch. Makesurethatthelampiscorrectlyconnectedtotheproject,andthatthemaleplugispluggedintothepowersocketinthewall. Then,uploadtheArduinosketchtotheboard. Youshouldseethatevery5seconds,therelayisswitching,turningthelamponandoff.

Besuretofixtherelayinapositionsuchthatitcannotbetouchedbyaccident.


3.4 PowerMeasurements&AutomaticLightingControl

Let’snowmovetothemainpartoftheproject:buildingtheArduinosketchforoursmartlamp. Webasicallyneedtocontinuouslymeasurethelightlevelandthecurrentconsumptionofthelamp,printthisdataontheLCDscreen,andchangethestateoftherelayaccordingly. Hereisthecompletecodeforthispart:

//Codeforthesmartlampproject

//Libraries

#include<Wire.h>


//Relaystate


booleanrelay_state=false;



//Definemeasurementvariables

floatamplitude_current;

floateffective_value;

floateffective_voltage=230;//Setvoltageto230V(Europe)or110V(US)

floateffective_power;

floatzero_sensor;

voidsetup()

{

//Initializethelcd

lcd.init();


lcd.backlight();

lcd.setCursor(1,0);


lcd.setCursor(1,1);


//Setrelaypintooutput


//Calibratesensorwithnullcurrent

zero_sensor=getSensorValue(A1);

//ClearLCD

delay(2000);

lcd.clear();

}

voidloop()

{

//Measurelightlevel


floatlight=(sensor_reading/1024*100);

//Performpowermeasurement

floatsensor_value=getSensorValue(A1);

//Converttocurrent

amplitude_current=(float)(sensor_value-zero_sensor)/1024*5/185*1000000;

effective_value=amplitude_current/1.414;

effective_power=abs(effective_value*effective_voltage/1000);

//Switchrelayaccordingly

//Ifthelightlevelismorethan75%,switchthelightsoff

if(light>75){


relay_state=false;

}

//Ifthelightlevelislessthan50%,switchthelightsoff

if(light<50){


relay_state=true;

}

//UpdateLCDscreen

//Displayrelaystate

lcd.setCursor(1,0);

lcd.print("Relay:");

if(relay_state){lcd.print("On");}

else{lcd.print("Off");}

//Displayenergyconsumption

lcd.setCursor(1,1);

lcd.print("Power:");

lcd.print(effective_power);

lcd.print("W");

//Displaylightlevel

lcd.setCursor(1,2);


lcd.print(light);

lcd.print("%");

//Wait500ms

delay(500);

}

//Getthereadingfromthecurrentsensor

floatgetSensorValue(intpin)

{

intsensorValue;

floatavgSensor=0;

intnb_measurements=100;

for(inti=0;i<nb_measurements;i++){

sensorValue=analogRead(pin);

avgSensor=avgSensor+float(sensorValue);

}

avgSensor=avgSensor/float(nb_measurements);

returnavgSensor;

}

ItstartsbyincludingthelibrariesrequiredfortheLCD:

#include<Wire.h>


WecancreatetheinstanceoftheLCDscreenatthispoint. Notethatyouwillhavetomodifythenumberoflinesdependingonyourscreen(4forthescreenIused):


Weneedtodeclarethepinonwhichtherelayisconnectedto,andavariabletostorethestateoftherelay:


booleanrelay_state=false;

Then,wehavetocreatesomevariabletocalculatethevalueofthecurrentandpowerconsumedbythelamp. Here,ifyouareusing110Vinsteadof230V,youwillneedtochangetheeffective_voltagevariabletothecorrectvalue:





floatzero_sensor;

Now,inthesetup()functionofthesketch,weinitializetheLCD:

lcd.init();

Wealsosetthepinoftherelayasanoutput:


Now,weneedtocalibratethecurrentsensor. ThecurrentsensorIusedinthisprojectisananalogsensor–itreturnsavoltageproportionaltothemeasuredcurrent. However,weneedtoknowwhatisthevoltageatwhichthesensormeasuresanullcurrent. Astherelayisswitchedofffornow,wearesuretohavenocurrentflowingthroughthelamp. WegetthenullcurrentvalueofthesensorbycallingafunctioncalledgetSensorValue()onthepinA1:


Wewon’tseethedetailsofthisfunction,butitbasicallyaveragesthereadingontheanalogpinoverseveralmeasurementstohaveastablereadingasanoutput. Westoretheresultinavariablecalledzero_sensor.

Finally,toendthesetup()function,wewaitforsometimebeforeclearingtheLCDscreen:

delay(2000);

lcd.clear();

Now,intheloop()functionofthesketch,wefirstreaddatafromtheanalogpinA0,whichreturnsavaluefrom0to1023. TheresolutionoftheAnalog-To-DigitalconverteroftheArduinoUnoboardis10bits,sowehave1024values. Then,wedividethisreadingby1024andmultiplyitby100tohavethelightlevelasapercentage:



Next,wegetthereadingfromthecurrentsensorusingthesamefunctionweusedbefore

(thataveragesthereadingsoverseveralsamples):


Fromthisvalue,weneedtocalculatethecurrent,andthenthepower. First,wecalculatethecurrentusingthecalibrationdataweacquiredbefore,andaformulagiveninthedatasheetofthesensor. Then,weconvertthiscurrenttoitseffectivevaluebydividingitbythesquarerootof2. Finally,wecalculatetheeffectivepowerbymultiplyingtheeffectivevalueofthecurrentwiththeeffectivevalueofthevoltage(andwealsodivideitby1000togettheresultinWatts):




Afterthat,wemakeadecisiononwhethertoswitchtherelayonornot. Ifthelightlevelismorethan75%,weswitchthelampoff,asthismeansitisbrightandwedon’tneedlights:

if(light>75){


relay_state=false;

}

Ifthelightlevelislessthan50%,weswitchthelighton:

if(light<50){


relay_state=true;

}

Ofcourse,youshoulduseyourownvaluesforthetwothresholds. Forexample,youcanmeasurethelightlevelsatnightwhentheroomisinanalmostcompletedarknesswithlightonlycomingfromyourlampandduringthedaywithsunlightseepingintoyourroom. Usingthesevalues,youcanmodifythetwothresholdsaccordingly.

Notethatitisnecessarytousetwothresholdshere. Rememberthatthereadingfromthephotocellcanoscillateabitovertime. Andyoudon’twantyourlamptocontinuouslyswitchonandoffifthereadingfromthephotocellisaroundthethreshold.

Finally,weprintdataontheLCDscreen. Wefirstprintthestateoftherelay:

lcd.setCursor(1,0);

lcd.print("Relay:");

if(relay_state){lcd.print("On");}

else{lcd.print("Off");}

Then,weprinttheeffectivepowerthatwecalculatedfromthecurrentsensorreading:

lcd.setCursor(1,1);

lcd.print("Power:");

lcd.print(effective_power);

lcd.print("W");

Afterthat,weprintthevalueoftheambientlightlevel:

lcd.setCursor(1,2);


lcd.print(light);

lcd.print("%");

Wealsowait500msbetweeneachmeasurement:

delay(500);



Itisnowtimetotestoursmartlamp. MakesurethatalltheconnectionsarecorrectlymadeandthenecessarycodeshavebeenuploadedtotheArduinoboard. Let’sassumeitiscurrentlybrightinyourhome:therelayshouldthereforebeswitchedoff. ThisiswhattheLCDscreenshouldbedisplayingaspicturedfrommyownproject:


Youcanseethatevenifthelightisoff,theArduinoboardmeasuressomepowerconsumedbythelamp. ThisisbecausetheACS712currentsensoroutputcanpickupnoiseduetoseveralfactorslikemagneticfields.

Now,tosimulateadarkroom,Isimplyputapieceoftissueontopofthephotocell.Instantly,themeasuredlightleveldropped,andthelampswitchedon:

Alsonotethatthemeasuredpowerwasaround25W,whichmakessenseasthelampisratedat30W.

Incaseyourprojectisnotworkingatthispoint,thereareseveralthingsyoucancheck.First,makesurethattherelay,theLCDscreenandthesensorsarecorrectlyconnectedtoyourArduinoboard. AlsomakesuretomodifythecodeaccordinglyifyouareusingasmallerLCDscreenthantheoneIusedonthisproject.

3.5 HowtoGoFurther

Let’ssummarizewhatwelearnedinthisproject. WebuiltasmartlampusingArduinoandsomebasiccomponents. Thelampisnowautomaticallyswitchingonoroffaccordinglytotheambientlightlevel. Wealsoaddedatwisttotheprojectbyaddingacurrentmeasurementdevice,whichtellsushowmuchpowerthelampisconsumingwhenitison. WealsoaddedanLCDscreenwhichdisplaysthestateofthelamp,thepowerconsumptionandtheambientlightlevel.

Youcanimprovethisprojectbyusingmoresensors. Forexample,youcancombineitwiththeprojectinthepreviouschapterandhavemoresensormeasurementsdisplayedontheLCDscreen. Youcanalsoaddmorecontrolstothelamptomakeitevensmarter. Forexample,youcanaddamotionsensortothemixtoswitchthelightonwhenthelightlevelisloworwhensomemotionisdetectedintheroom

Chapter4

XBeeMotionSensorsInthepreviouschaptersofthisbook,webuilt“self-contained”homeautomationsystems,whichcouldworkcompletelyautonomously,withoutcommunicatingwiththeexternalworld. However,that’snothowmostcommercialhomeautomationsystemswork.Usually,thecomponentsinthesesystemscommunicatewitheachotherwirelessly. Andthat’sexactlywhatwearegoingtodointheremainingchaptersofthisbook.

TostartwithwirelesshomeautomationsystemsbasedonArduino,wearegoingtouseatechnologythatiswidelyusedinhomeautomationsystems:XBee. XBeeisatechnologybuiltontheZigBeestandard,whichdefineslow-power,digitalradiocommunicationsbasedontheIEEE802.15standard. Itwasmadeforsystemsthatrequiresmalldatatransfer(likesensors),runningonbatteries,andthathavetobesecure. Needlesstosay,it’stheperfecttechnologyforhomeautomationsystems.

Inthisproject,wearegoingtotakeanewlookataprojectwehavealreadybuilt:thesimplealarmbasedonArduinoandaPIRmotionsensor. WearegoingtotakethesamesensorandArduino,andaddanXBeemoduletoit. Wearealsogoingtobuildaninterfaceonyourcomputer,soyoucanmonitorthestateofmanyoftheseXBeemotionsensorsfromyourwebbrowser.


Let’sfirstseewhatweneedforthisproject. Therearetwodistinctthingsthatwewillhavetobuildinthisproject. Ononeside,wewillhavetheXBeemotionsensors,andtheotherside,wewillhaveoneXBeemodulethatwillbeconnectedtoyourcomputerviaUSB.

ForoneXBeemotionsensor,youwillfirstneedanArduinoboard. IusedagainanArduinoUnoboardforthisproject.

Then,youneedamotionsensor. Forthisproject,IusedthesamePIRmotionsensorthatwealreadyusedinthefirstprojectofthisbook.

Next,youneedtointerfacetheXBeemodulewiththeArduinoboard. ToconnecttheXBeemoduletoArduino,IusedaSparkFunXBeeshieldforArduino. ItintegratesasocketforanyXBeemodule,andalsoaswitchtoconnectanddisconnecttheXBeemodulefromtheArduinomicrocontrollerSerialport. We’llseelaterinthischapterthatitisveryuseful.

FortheXBeemodules,IusedSeries2XBeemodules,withawireantenna. Series1aremucheasiertouse,butSeries2addthepossibilitytocreatemeshednetworks,andtotargetagivenmodule,whichissomethingwewilluseinthischapter.

HereisapictureoftheArduinoUnoboardwiththeXBeeshieldonit,withoneXBeemodulealreadypluggedin:

HereisalistofallcomponentsforoneXBeemotionsensor,alongwiththelinkswhereyoucouldpurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)PIRmotionsensor(https://www.adafruit.com/products/189)ArduinoXBeeshield(https://www.sparkfun.com/products/10854)XBeeSeries2modulewithwireantenna(https://www.sparkfun.com/products/11215)Jumperwires(http://www.adafruit.com/product/758)

Now,weneedtogetyourcomputersomeXBeeconnectivity. Indeed,unlikeBluetoothorWiFi,computersdon’tcomewithbuilt-inXBeeconnectivity.

ToconnectanXBeemoduletomycomputer,IchoseaUSBexplorermodulefromSparkfun. YoucanmountanyXBeemoduleonit,andyoucanconnectitviaUSBtoyourcomputer. ItbehaveslikeaSerialport,whichmeansyoucansendmessagestoitviatheArduinoIDEserialmonitor.

FortheXBeemodule,IchosethesamemoduleasfortheXBeemotionsensors.

HereisapictureoftheXBeeexplorerboardwiththeXBeemodulemountedonit:


https://www.adafruit.com/products/189




TouseXBeeonyourcomputer,youwillneedthesecomponents:

USBXBeeexplorerboard(https://www.sparkfun.com/products/11812)XBeeSeries2modulewithwireantenna(https://www.sparkfun.com/products/11215)

Onthesoftwareside,youneedtohavethelatestversionoftheArduinoIDEinstalledonyourcomputer,aswellastheaRESTlibraryforArduinowhichyoucanfindonthefollowinglink:

https://github.com/marcoschwartz/aREST

Toinstallagivenlibrary,simplyextractthefolderinyourArduino/librariesfolder(orcreatethisfolderifitdoesn’texistyet).




4.2 BuildinganXBeeMotionSensor

WearenowgoingtoseehowtobuildoneXBeemotionsensor. Ifyouwanttousemanyofthemforthisproject,justrepeatthefollowingstepsforeachmodule.

Theconfigurationofthisprojectisactuallyverysimple. First,plugtheXBeeshieldontheArduinoboard,andplugoneXBeemoduleontheshield. ForthePIRmotionsensor,connecttheGNDpintotheArduinoground,VCCtotheArduino5Vpin,andSIGpintotheArduinopin8. Youshouldendupwithsomethingsimilartothefollowingpicture:

YouwillalsoneedtoputtheswitchontheXBeeshieldtothecorrectposition. Atthispoint,wewanttoprogramtheArduinoboardtosettheswitchsuchthattheXBeemoduleisnotconnectedtotheSerialportoftheArduinomicrocontroller. Todoso,puttheswitchon“DLINE”:

Finally,alsoconnecttheXBeeexplorerboardwiththeXBeemoduleonittoyourcomputer.

4.3 TestingtheMotionSensor

Wearenowgoingtotestthemotionsensor. WewillwriteasimplesketchthatcontinuouslyprintsthestatusofthemotionsensortotheSerialportoftheArduino. Fornow,leavetheswitchoftheXBeeshieldto“DLINE”. Hereisthecompletesketchforthispart:

//Simplemotionsensor

intsensor_pin=8;

voidsetup(){

Serial.begin(9600);

}

voidloop(){

//Readsensordata

intsensor_state=digitalRead(sensor_pin);

//Printdata

Serial.print("Motionsensorstate:");

Serial.println(sensor_state);

delay(100);

}

ThesketchstartsbydeclaringwhichpinthePIRmotionsensorisconnectedto:

intsensor_pin=8;

Inthesetup()functionofthesketch,westarttheSerialport:

Serial.begin(9600);

Intheloop()functionofthesketch,wereadthePIRmotionsensorpin:

intsensor_state=digitalRead(sensor_pin);

Finally,weprintthestateofthatpinevery100msontheSerialport:

Serial.print("Motionsensorstate:");

Serial.println(sensor_state);

delay(100);

NotethatthecompletecodeforthissectioncanbefoundinsidetheGitHubrepositoryofthebook:


It’snowtimetotestthisfirstsketchofthischapter. UploadthesketchtotheArduinoboard,andopentheSerialmonitor(makingsurethattheSerialspeedissetto9600). Youcanpassyourhandinfrontofthesensor,andyoushouldseethatthestateofsensor


changes:

Motionsensorstate:0

Motionsensorstate:0

Motionsensorstate:0

Motionsensorstate:0

Motionsensorstate:1

Motionsensorstate:1

Motionsensorstate:1

Motionsensorstate:1

Motionsensorstate:0

Motionsensorstate:0

Motionsensorstate:0

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyouhavecorrectlypluggedthemotionsensorintotheArduinoboardasdefinedearlierinthechapter. Then,makesurethatyouhavecorrectlyuploadedthelatestversionofthecode.

4.4 UsingtheXBeeModule

Inthissection,wearegoingtousetheXBeemodulethatissittingontheXBeeshieldtoaccessthemotionsensorwirelessly. WearegoingtowriteasimpleArduinosketchwhichmakesuseoftheaRESTlibrarytoreceiveandhandlerequestscomingfromtheoutside.

ButthefirstthingwehavetodoistoconfigureourXBeeradios. Bydefault,allXBeemodulesareconfiguredtousethesamecommunicationchannelcalledthePAN(PersonalAreaNetwork)ID.Thisisgoodtotestthemoutofthebox,butthisisnotgoodatallwhenyouactuallywanttousetheminyourhome. IfyouleavethemonthedefaultPANID,theywillbroadcastmessagesonalldeviceswiththesamePANID,includingthoseofyourneighbors! Worse,somebodycouldactuallyhackintoyourXBeesensorsfromtheoutside.

Wealsoneedtosetourradioscorrectlybygivingthemroles. InaSeries2XBeenetwork,oneoftheradiosshouldbethe‘coordinator’ofthenetwork. Withoutone,itwillsimplynotworkatall. Theotherradioscanbeeither‘routers’thatcanrelaymessages,or‘EndDevices’thatsimplygetmessagesfromthenetwork. Becausewehaveasimplenetworkhere,wewillsimplyconfiguretheXBeeradioconnectedtoourcomputertobeacoordinator,andtheothertobeenddevices.

Therefore,weneedtochangealltheseparameters. ThisisactuallyeasytodousingtheofficialsoftwaretoconfigureXBeemodulescalledXCTU.Youcandownloaditatthefollowingaddress:

http://www.digi.com/support/productdetail?pid=3352&type=utilities

Onceitisinstalled,openthesoftware,andconnecttheXBeemoduleyouwanttoconfiguretotheXBeeexplorermodulewhichisconnectedviaUSBtoyourcomputer. BylookingattheSerialportoftheexplorermodule,youcanaccessthesettingsofthisXBeemodule.

First,lookfor“PANID”inthe“RadioConfiguration”window:

http://www.digi.com/support/productdetail?pid=3352&type=utilities

Fromthismenu,youcansetthePANIDfortheXBeemodulethatiscurrentlypluggedinsidetheXBeeexplorerboard. SimplyrepeattheoperationforeveryXBeemoduleyouwanttoconfigure.

Now,wewillgiverolestoourXBees. PlugthemodulewhichwillbethecoordinatorintotheXBeeexplorer. Addthedeviceusingtheleftmenuagain,andthenclickontheupdatefirmwarebuttononthetopmenubar(theonewithalittlearrowgoingintothechip).

Fromthere,youwillbeabletoselectthefirmwarewewantforourcoordinatorXBee. Wehavetoselect‘XB24-ZB’ontheleft,andthen‘ZigBeeCoordinatorAPI’fromthelist.Selectthelatestfirmwareversion,andconfirmourchoice:

Afterawhile,youwillseethatyourdeviceisnowconfiguredasanXBeecoordinatorin

APImode:

StillforthisXBeedevice,weneedtogodownthelistofparameters,andchoose‘2’intheAPIEnableparameter,andwritetheparameterintotheXBeeradiowiththerightbutton:

Finally,weneedtoconfiguretheotherXBeeradiosasendpoints. Foreachofthem,connectthemtotheXBeeexplorer,clickonthebuttontowritethefirmwareagain,select‘XB24-ZB’ontheleft,andselect‘ZigBeeEndDeviceAT’fromthelist. Confirm,andthisiswhatyoushouldget:

WearenowgoingtobuildthisArduinosketchontopofthetestsketch,soIwillonlydefinethecodeadditionshere. Hereisthecompletesketchforthispart:

//Libraries

#include<SPI.h>

#include<aREST.h>

//MotionsensorID

char*xbee_id="2";

//CreateArduRESTinstance

aRESTrest=aREST();

voidsetup(){

//StartSerial

Serial.begin(9600);

//GivenameandIDtodevice

rest.set_id(xbee_id);

rest.set_name("motion2");

}

voidloop(){

//HandleRESTcalls

rest.handle(Serial);

}

Thissketchstartsbyincludingthecorrectlibrariesforthesketch:

#include<aREST.h>

WealsodefinetheIDofthesensor. Thisisreallyusefulifyouhavemanymotionsensorsinyourhome. MakesuretogivethemdifferentIDs:

Stringxbee_id="1";

WealsoneedtocreateaninstanceoftheaRESTlibrary:

aRESTrest=aREST();

Inthesetup()functionofthesketch,westarttheSerialport. Notethatitisreallyimportanttouseaspeedof9600hereasitisthedefaultspeedofXBeemodules:

Serial.begin(9600);

WealsosettheIDofthedevicethatwedefinedbefore:


Finally,intheloop()functionofthesketch,wesimplyhandletherequestscomingfromtheSerialportusingtheaRESTlibrary:




It’snowtimetotestthissketch. UploadthesketchtotheArduinoboard. Then,puttheswitchoftheXBeeshieldto“UART”sothattheXBeemodulecandirectlycommunicate


withtheArduinomicrocontrollerviatheSerialport. NotethatifyouneedtoprogramtheArduinoboardagain,youneedtoswitchitbackto“DLINE”.

YoushouldalsomakesurethattheXBeeexplorermoduleispluggedinyoursystem. IfyouarerunningunderWindowsorOSX,youmightneedadditionaldriverstoinstallforthisUSBboard. Youcanfindallthedownloadandinstallationdetailshere:

http://www.ftdichip.com/FTDrivers.htm

Now,youneedtolocatetheSerialportcorrespondingtotheXBeeexplorerboardconnectedtoyourcomputer. YoucandosobylookingattheTools>SerialPortmenuoftheArduinoIDE.Forexample,mineiscalled“/dev/cu.usbserial-A702LF8B”. OnWindows,itwilllooklike‘COM3’. Alsowriteitdownforyouwillneeditlaterwhenbuildingtheinterfaceforyourmotionsensors.

OpentheSerialmonitoroftheArduinoIDE.Makesurethatthespeedissetto9600,andthattheendlinecharacterissetto‘Carriagereturn’. NotethatbecausewearenowconnectedtotheXBeeexplorerboard,allcommandsthatyouaresendingnowarebeingsenttoallXBeemodulesinyourhome.

IntheSerialmonitor,type:

/id

ThiswillsimplyquerytheIDoftheallXBeeboardsthatareinyourhome. WhenItestedmyproject,Ionlyhadoneinmyhome. Itrespondedwith:

{"id":"1","name":"","connected":true}

Afterthisstep,wearegoingtoreadthestatusofthemotionsensor. Remember,itisconnectedtopinnumber8. Toreadfromthispin,simplytype:

/digital/8

Thesensorshouldanswerwiththefollowingmessage:

{"return_value":1,"id":"1","name":"","connected":true}

Ifthesensorsareansweringtothequeriesatthispoint,itmeansthattheyareworkingcorrectlyandthatyoucanaccessthemwirelessly.

Incaseitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyouhaveuploadedthelatestversionofthecode. YoucanfinditinsidetheGitHubrepositoryofthebook. Also,makesurethattheXBeeexplorerboardiscorrectly

http://www.ftdichip.com/FTDrivers.htm

pluggedintoyourcomputerbycheckingthattheproperdriversareinstalled. Finally,makesurethattheXBeeshieldissettothe‘UART’position.

4.5 BuildingtheCentralInterface

Wearenowgoingtobuildtheinterfacethatyouwillusetomonitorthemotionsensorsfromyourcomputer. Usingthisinterface,youwillbeabletoseethestateofeachsensorviaXBee,rightinyourwebbrowser.

TheinterfacethatwearegoingtodevelopisbasedonNode.js,whichallowsthecodingofserver-sideapplicationsinJavaScript. First,wearegoingtocodethemainfilecalledapp.js,whichwewillrunlaterusingthenodecommandinaterminal. Hereisthecompletecodeforthisfile:

//Modules

varexpress=require('express');

varapp=express();

//Defineport

varport=3000;

//Viewengine

app.set('viewengine','jade');

//Setpublicfolder

app.use(express.static(__dirname+'/public'));

//Rest

varrest=require("arest")(app);

rest.addDevice('xbee','/dev/tty.usbserial-A702LF8B');

//Serveinterface

app.get('/',function(req,res){

vardevices=rest.getDevices();

res.render('interface',{devices:devices});

});

//Startserver

app.listen(port);

console.log("Listeningonport"+port);

Itstartsbyimportingtheexpressmodule:


Then,wecreateourappbasedontheexpressframework,andthesettheportto3000:

varapp=express();

varport=3000;

Wealsoneedtotelloursoftwarewheretolookforthegraphicalinterfacethatwearegoingtocodelater. WealsosetthedefaultviewenginetoJade,whichaswewillseeisasimplifiedwaytocodeinHTML:



Atthispoint,wealsoimportthenode-aRESTmodule,thatwillhandleallthecommunicationbetweentheinterfaceandthemodule. Here,wealsoneedtodefinetheSerialportonwhichtheXBeeexplorermoduleisconnectedto:



ThiswillautomaticallylookforallXBeemodulesinthesamenetworkasourcoordinatorradio,andaddthemautomaticallytotheserversowecanaccessthemfromtheinterface.

Now,wearegoingtobuildthemainrouteofourserver. WedefinethisroutebylinkingtherootURLofourservertothecorrespondingJadefile. Becausewewanttobuildtheinterfaceautomaticallydependingonhowmanydevicesarepresent,weneedtogetallthedevicesfirst,andthentransmitthisdatatotheJadefilesoitcanberenderedcorrectly:




});

Finally,stillinthisapp.jsfile,westarttheappwiththeportwedefinedbefore,andwriteamessageintheconsole:

app.listen(port);


Thiswasforthemainserverfile. Now,wearegoingtobuildtheinterfaceitself. Let’sseethecontentofthisJadefilefirst. Thisfileislocatedinthe/viewsfolderofourproject.Hereisthecompletecodeforthisfile:

doctype

html

head

titleXBeemotionsensors

link(rel='stylesheet',

href='//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css')

script(src="https://code.jquery.com/jquery-2.1.1.js")

script(src="/js/interface.js")

body

.container

.row

h1XBeemotionsensors

if(devices!='[]')

eachdeviceindevices

if(device.type=='xbee')

.row

.col-md-4

h3Sensor#{device.id}

.col-md-4

h3.display(id=device.id)

JadeisbasicallyatemplatelanguagethatallowstowriteHTMLwithlesscodethanHTMLitself,andalsotoinsertsomecoderightintotheinterfacefile,togenerateHTML

dependingonsomevariables.

ThefilestartsbyimportingthedifferentJavaScriptfileswhichwillhandletheclickontheinterface,andsendthecorrectcommandstotheArduinoboard:

script(src="https://code.jquery.com/jquery-2.1.1.js")


WewillalsousetheTwitterBootstrapCSSframeworktogiveourinterfaceabetterlook:


href='//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css')

Themainpartoftheinterfaceconsistsingoingthroughthelistofallsensorsthatweredetectedbefore,andbuildarowforeachsensor. Thisisdonebythefollowingpieceofcode:

if(devices!='[]')

eachdeviceindevices


.row

.col-md-4


.col-md-4


Next,wearegoingtohavealookatthecodeinsidetheinterface.jsfile,whichdefineshowtheinterfaceoftheprojectisworking. ItwillmakethequeriestotheboardviatheNode.jsserver,andupdatetheinterfaceaccordingly. Thisfileislocatedinthepublic/jsfolderoftheinterface. Hereisthecompletecodeforthisfile:

$(document).ready(function(){

$.get('/devices',function(devices){

//Setinputs

for(i=0;i<devices.length;i++){

//Getdevice

vardevice=devices[i];

//Setinput

$.get('/'+device.name+'/mode/8/i');

}

setInterval(function(){


//Getdevice


//Getdata

$.get('/'+device.name+'/digital/8',function(json_data){

//Updatedisplay

if(json_data.return_value==0){

$("#"+json_data.id).html("Nomotion");

$("#"+json_data.id).css("color","red");

}

else{

$("#"+json_data.id).html("Motiondetected");

$("#"+json_data.id).css("color","green");

}

});

}

},2000);

});

});

ThemainpartofthisJavaScriptfileisprogrammedtocontinuouslycheckthestatesofthesensorsbysendingthemqueries. ThisisdoneinsideasetInterval()function:


Insidethisfunction,wegothroughalldevices,andsendthemacommandtoreadthepinonwhichthemotionsensorsareconnectedto:


TheaRESTlibraryalwaysreturndatainaJSONcontainer,soitisreallyeasytoaccessthisdatawithinJavaScript. Weneedtoknowthestateofthatmotionsensor. Thisisstoredinthereturn_valuefield. Ifthedatainthisfieldisequalto0,wesettheindicatorofthissensorto‘Nomotion’inred. Otherwise,wesetittogreenwiththe‘Motiondetected’message,meaningmotionwasdetectedbythissensor:




}

else{



}

Afterthat,weclosethesetInterval()function,repeatingtheloopeverytwoseconds:

},2000);



It’snowtimetotesttheinterface. MakesurethatyoudownloadallthefilesfromtheGitHubrepository,andupdatethecodewithyourowndataifnecessary,liketheSerialportcorrespondingtoyourXBeeexplorerboard. Also,makesurethattheArduinoboardisprogrammedwiththecodewesawearlierinthischapter.


Gotothefolderoftheinterfacewithaterminalandtypethefollowingcommandtoinstallthenode-aREST,jade&expressmodules:

sudonpminstallarestexpressjade

NotethatifyouareunderWindows,youhavetoleaveoutthesudoinfrontofthecommands. ItisalsorecommendedtousetheNode.jscommandprompt. Finally,youcanstarttheNode.jsserverbytyping:

sudonodeapp.js

Youshouldbegreetedwiththefollowingmessageintheterminal:

Listeningonport3000

YoushouldalsoseeintheterminalthatyourXBeeradiosareautomaticallydiscoveredandaddedtothesystem. Youcannowgototheyourwebbrowserandtype:

localhost:3000

Youshouldseetheinterfaceofourprojectbeingdisplayed:

Totestthisproject,Iusedtwomotionsensors. Toillustratethebehaviorofonemodule,IsimplypassedmyhandinfrontofthesensorwithIDnumber1. Thecorrespondingindicatorimmediatelyturnedtogreen. Ofcourse,ifyouhavemoresensors,theinterfacewillautomaticallybemodified.

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyouhavedownloadedthelatestversionofthecodefromtheGitHubrepositoryofthebook. Also,makesurethatyouhavecorrectlymodifiedthefilestouseyourownsettings,liketheSerialportforyourXBeeexplorermodule. Finally,makesureyouhaveinstalledtherequiredNodemoduleswithnpmbeforestartingthewebinterface.

4.6 HowtoGoFurther

Let’ssummarizewhatwelearnedinthisproject. WetooktheprojectwealreadybuiltinChapter1andaddedwirelesscapabilitiestoitusingXBee. WelearnedhowtointerfaceXBeemoduleswithArduino,andbuildXBeemotionsensorswithit. Wewereabletomonitorthestateofseveralwirelessmotionsensorsfromyourwebbrowser.

Thereareofcoursemanywaystogofurtherwiththisproject. Theeasiestthingistoaddmoremotionsensorstotheprojecttocoverallyourhome. Youcanalsoadddifferentkindsofdigitalsensorstotheproject. Forexample,youcanusethesamecodetomonitorthestateofcontactsensorswhichyoucanputondoorsandwindows.

YoucanalsousethesameprinciplesseeninthischaptertomonitorotherdatausingXBee,likemeasurementscomingfromtemperaturesensors.

Chapter5

BluetoothWeatherStationInthischapter,wearegoingtogivewirelesscapabilitiestotheprojectwealreadysawinChapter2. WearegoingtobuildawirelessweathermeasurementstationusingBluetooth.

Thestationwillmeasuretemperature,humidityandlightlevelintheroomwheretheprojectislocated,anddisplaythisdataonanLCDscreen. However,inthisnewprojectwewilladdaBluetoothmoduletotheprojecttobeabletomonitorthemeasureddatafromanywhereinyourhome. Wearegoingtobuildaninterfaceonyourcomputersoyoucancheckthemeasurementsdonebythestationinsideyourwebbrowser.


Forthisproject,youwillofcourseneedanArduinoUnoboard. YoucanalsouseotherArduinoboardslikeanArduinoMegaorLeonardo,itwillworkjustfineaswell.

Fortemperatureandhumiditymeasurements,youwillalsoneedaDHT11sensor,alongwitha4.7Kresistor. YoucanalsouseaDHT22sensorwhichismoreprecise,youwillonlyhaveonelineofcodetochange.


YouwillalsoneedaLCDscreentodisplaythemeasurements. Iuseda4x20charactersLCDsoIcandisplayuptofourdifferentmeasurementsatthesametime. YoucanofcourseuseasmallerLCDscreen,butyouwillonlybeabletodisplaythetemperature&humidityatthesametime,forexample.

ThescreenIusedforthisprojectisalsousinganI2CinterfacetocommunicatewiththeArduinoboard. Ireallyrecommendusingascreenwhichsuchaninterface,asthereareonlytwodatapinstoconnecttotheArduinoboardinordertousetheLCD.

FortheBluetoothmodule,IusedaBluetooth2.1modulefromAdafruit. ThismoduleinterfacesdirectlywiththeSerialportoftheArduinoboard,whichmakesitveryconvenient. Youcanbasicallyuseanymodule(includeBluetooth4.0modules)thatcaninterfacedirectlywiththeSerialportoftheArduinomicrocontroller. ModulesthatrequiretheirownlibrariesforArduino(forexamplebasedonthenRF8001chip)won’tworkoutoftheboxforthisproject. ThisisapictureofthemoduleIused:

Finally,Iusedabreadboardandsomemale-malejumperwirestomakethedifferentelectricalconnections.

Thisisalistofallcomponentsusedinthisproject,alongwithlinkstopurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)DHT11sensor(http://www.adafruit.com/product/386)Photocell(http://www.adafruit.com/product/161)10kOhmresistor(https://www.sparkfun.com/products/8374)LCDdisplay(http://www.robotshop.com/en/dfrobot-i2c-twi-lcd-module.html)AdafruitEZ-LinkBluetoothmodule(https://www.adafruit.com/products/1588)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

YouwillneedtheaRESTlibraryforArduinowhichyoucanfindonthefollowinglink:


YouwillalsoneedthelibraryfortheDHTsensor:











AndtheLiquidCrystallibraryfortheLCDscreen:


Toinstallalibrary,simplyputthefolderinyour/libraries/folderofyoumainArduinofolder.



5.2 BuildingtheBluetoothWeatherStation

Thehardwareconnectionsforthisprojectareactuallyquitesimple:wehavetoconnecttheDHT11sensor,thepartresponsibleforthelightlevelmeasurementwiththephotocell,theLCDscreen,andfinallytheBluetoothmodule.

Tohelpyouout,thefollowingpicturesummarizesthehardwareconnections,withouttheLCDscreenshown:


First,connecttheArduinoUno+5Vpintotheredrailonthebreadboard,andthegroundpintothebluerail.

ToknowwhichpintoconnectfortheDHT11sensor,thispicturecanhelpyouout:


Then,connectpinnumber1oftheDHT11sensor(VCC)totheredrailonthebreadboard,andpinnumber4(GND)thebluerail. Alsoconnectpinnumber2ofthesensortopinnumber7oftheArduinoboard. TofinishupwiththeDHT11sensor,connectthe4.7kOhmbetweenpinnumber1and2ofthesensor.

Forthephotocell,firstplacethecellinserieswiththe10kOhmresistoronthebreadboard. Then,connecttheotherendofthephotocelltotheredrailonthebreadboard,andtheotherendoftheresistortotheground. Finally,connectthecommonpinoftheresistor&thephotocelltotheArduinoUnoanalogpinA0.

Now,wearegoingtoconnecttheLCDscreen. AsweareusingaLCDwithanI2Cinterface,therewillonlybetwowirestoconnectforthesignal,andtwoforthepower.ConnecttheLCDpincalledVCCtotheredrailonthebreadboard,andtheGNDpintothebluerailonthebreadboard. Then,connecttheLCDpinSDAtotheArduinopinA4,andtheSCLpintoArduinopinA5.

TheBluetoothmoduleisalsoquiteeasytoconnect. First,thepowersupply. ConnecttheVinpin(orVCC,dependingonyourmodule)totheredpowerrail,andtheGNDpintothebluepowerrail. Then,wehavetoconnecttheSerialportoftheBluetoothmoduleto

theArduinoboard. ConnecttheRXpinofthemoduletotheTXpin(pinnumber1)oftheArduinoboard,andtheTXpinofthemoduletotheRXpin(pinnumber0)oftheArduinoboard.

Thisisapictureofthefullyassembledprojectsoyoucanhaveanideaonhowthecompleteprojectlookslike:

ThispictureisacloserlookattheBluetoothmoduleonthebreadboard:

5.3 PairingtheBluetoothModule

Beforeweproceedfurther,wearegoingtotestourassembledhardware. WealreadymadethetestofthedifferentsensorsinChapter2,soyoucanrefertothischaptertotestthesensorsoftheproject. Here,wearesimplygoingtocheckifwecanaccesstheBluetoothmodule.

Simplypoweruptheproject,forexamplebyconnectingaUSBcablebetweentheArduinoboardandyourcomputer. Then,gotheBluetoothpreferencesofyourcomputer,andyoushouldseetheBluetoothmoduleappearinginthelistofnearbyBluetoothdevices:

Clickon“Pair”topairtheBluetoothmodulewithyourcomputer. Then,goovertoyourArduinoIDE.OpentheTools>SerialPortlist. YoushouldseethatanewSerialportisavailable,containing“AdafruitEZ”inthenameoftheSerialport(orthenameoftheBluetoothmodulethatyouareusing):

Ifthisisnotthecase,simplycloseandre-opentheArduinoIDE.IftheBluetoothmoduleiscorrectlypairedwithyourcomputer,thereisnoreasonforitnottoappearinyourArduinoIDE.

5.4 RemoteTemperatureMeasurements

NowthatwearesurethatwecanpairtheBluetoothmodulewithyourcomputer,wearegoingtowriteasketchtoreceivecommandsviaBluetooth. Todoso,wewillusetheaRESTlibraryagain,thatwealreadyusedinthepreviouschaptertohandlecommandscomingviaBluetooth. Thisisthecompletecodeforthispart:

//Codetomeasuredata&makeitaccessiblevia

//Libraries

#include<Wire.h>


#include"DHT.h"

#include<aREST.h>

//DHTsensor

#defineDHTPIN7

#defineDHTTYPEDHT11



//DHTinstance


//CreateaRESTinstance

aRESTrest=aREST();

//VariablestobeexposedtotheAPI

inttemperature;

inthumidity;

intlight;

voidsetup()

{

//StartSerial

Serial.begin(115200);

//ExposevariablestoRESTAPI

rest.variable("temperature",&temperature);

rest.variable("humidity",&humidity);

rest.variable("light",&light);

//Setdevicename&ID

rest.set_id("1");

rest.set_name("weather_station");

//Initializethelcd

lcd.init();


lcd.backlight();

lcd.setCursor(1,0);


lcd.setCursor(1,1);


//InitDHT

dht.begin();

//ClearLCD

lcd.clear();

}

voidloop()

{

//MeasurefromDHT

temperature=(int)dht.readTemperature();

humidity=(int)dht.readHumidity();

//Measurelightlevel


light=(int)(sensor_reading/1024*100);

//HandleRESTcalls



lcd.setCursor(1,0);




lcd.print("C");

//Displayhumidity

lcd.setCursor(1,1);



lcd.print("%");

//Displaylightlevel

lcd.setCursor(1,2);


lcd.print(light);

lcd.print("%");

//Wait100ms

delay(100);

}

First,weneedtoincludetherequiredlibrariesfortheproject:

#include<Wire.h>


#include"DHT.h"

#include<aREST.h>

WealsohavetodefinethepinsonwhichtheDHTsensorisconnectedto,andthetypeofthesensor:

#defineDHTPIN7

#defineDHTTYPEDHT11

WealsoneedtocreateaninstanceoftheLCDscreen:


Then,wehavetocreateaninstanceoftheDHTsensor:



aRESTrest=aREST();

Finally,justbeforethesetup()function,wedeclarethedifferentvariablesthatwillstore

themeasurementsdonebytheweatherstation:

inttemperature;

inthumidity;

intlight;

Now,inthesetup()functionofthesketch,weinitializetheSerialport:


Notethathere,itisimportanttostartitusing115200bpsastheBluetoothmoduleisoperatingatthisspeed. IftheBluetoothmoduleyouareusingforthisprojectisdifferent,youneedtochangetheSerialspeedaccordingly.

Then,wehavetoexposethedifferentmeasurementvariablestotheaRESTAPI,sowecanaccessthemviaBluetooth:

rest.variable("temperature",&temperature);

rest.variable("humidity",&humidity);


WealsogiveanIDtothestation,andsomename:

rest.set_id("1");

rest.set_name("weather_station");

Finally,toendthesetup()function,weinitializetheLCDscreenandstarttheDHTsensor:

lcd.init();

dht.begin();

Now,intheloop()function,wewillfirstmaketherequiredmeasurements,handlethecallscomingfromtheBluetoothmodule,andfinallydisplaythemeasurementsontheLCDscreen. First,wegetthemeasurementsfromtheDHTsensor:

temperature=(int)dht.readTemperature();

humidity=(int)dht.readHumidity();

Wealsogetdatafromthephotocell,andconvertthisresultto%:



Afterthat,wehandletherequestscomingfromtheBluetoothmodule:


Finally,weendthesketchbydisplayingthedifferentmeasurementsontheLCDscreen.

Forexample,onthefirstlineofthescreenIchosetodisplaythetemperature:

lcd.setCursor(1,0);




lcd.print("C");



It’snowtimetotesttheproject. Butfirst,weneedtodoalittlehardwaremodification.Indeed,theSerialportiscurrentlydirectlyconnectedtotheBluetoothmodule,whichpreventsusfromprogrammingtheArduinoboardusingtheUSBcable. Sofirst,disconnectthewiresgoingfromtheBluetoothmoduletotheArduinoboard(TX&RX).

Now,youcanuploadthesketchtotheArduinoboardasusual. Whenthisisdone,reconnecttheTXandRXwiresbetweentheBluetoothmoduleandtheArduinomodule.Whenthisisdone,youcanpairagaintheBluetoothmodulewithyourcomputer,andthenselecttheBluetoothSerialport(theonestartingwithcu. andcontainingthenameofyourmodule).

Then,opentheSerialmonitor,andselectthecorrectSerialspeedthatyoudefinedinthesketch. Alsomakesurethattheendlinecharacterissetto‘Carriagereturn’,justnexttotheSerialspeed. Youcannowsimplytype:

/id

TheprojectshouldanswerwiththeID&nameoftheweatherstation:

{"id":"1","name":"weather_station","connected":true}

Wecanalsotestthereadoutofonevariable. Forexample,thelightlevelwiththefollowingcommand:

/light

Youshouldgettheanswerfromtheproject:

{"light":83,"id":"1","name":"weather_station","connected":true}

Ofcourse,atthesametimetheprojectshouldprintallthemeasurementsontheLCDscreen:


Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyoucorrectlyassembledthehardware,aswesawearlierinthischapter. Also,makesurethatyoucorrectlyuploadedthecodeforthispart,andthatyouconnectedagaintheBluetoothmoduletoyourArduinoboardviatheSerialpins.

5.5 BuildingtheServerInterface

WearenowgoingtobuildaninterfaceforourBluetoothweatherstation,sowecanmonitorthedifferentmeasurementsmadebythestationfromawebbrowser. WewillstillbeabletocheckthemeasurementsfromtheLCDscreen,butwewillalsohavethepossibilitytowatchthesemeasurementsremotely.

Notethatthispartissimilartowhatwedidinthepreviouschapterfortheinterface. Ifyoufeelconfidentwithit,youcanskipthebeginningofthecodewalkthrough.

Asfortheotherinterfaceswedevelopedinthisbook,theinterfacewearegoingtodevelopisbasedonNode.js. First,wearegoingtocodethemainfilecalledapp.js,whichwewillrunlaterusethenodecommandinaterminal. Thisisthecompletecodeforthisfile:

//Modules


varapp=express();

//Defineport

varport=3000;

//Viewengine


//Setpublicfolder


//Rest


rest.addDevice('serial','/dev/tty.usbmodem1a12121',115200);

//Serveinterface


res.render('interface');

});

//Startserver

app.listen(port);





varapp=express();

varport=3000;

Wealsoneedtotelloursoftwarewheretolookforthegraphicalinterfacethatwearegoingtocodelater,andwealsosetJadeasourdefaultviewengine:



Wealsoneedtoimportthenode-aRESTmodule,andalsoaddthedeviceconnectedtoyourBluetoothSerialport. Notethathere,youneedtoinsertyourownSerialportaddresssotheinterfacecancommunicatewithyourBluetoothmodule:


rest.addDevice('serial','/dev/tty.AdafruitEZ-Link06d5-SPP',115200);

Now,wearegoingtobuildthemainrouteofourserver. WedefinethisroutebylinkingtherootURLoftheservertothecorrespondingJadefile:



});


app.listen(port);


Thiswasforthemainserverfile. Now,wearegoingtobuildtheinterfaceitself. Let’sseethecontentoftheJadefilefirst. Thisfileislocatedinthe/viewfolderofourproject. Thisisthecompletecodeforthisfile:

doctype

html

head

titleBluetoothWeatherStation

link(rel='stylesheet',href='/css/interface.css')


href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css")

script(src="https://code.jquery.com/jquery-2.1.1.min.js")


body

.container

h1BluetoothWeatherStation

.row.voffset

.col-md-6

.display#temperatureDisplayTemperature:

.col-md-6

.display#humidityDisplayHumidity:

.row

.col-md-6

.display#lightDisplayLightlevel:

.col-md-6

.status#statusStationOffline

ThefilestartsbyimportingthedifferentJavaScriptfilesthatwillhandletheclickontheinterface,andsendthecorrectcommandstotheArduinoboard:



WealsousetheBootstrapframeworkagaintogiveabetterlooktoourinterface:




Then,themainpartoftheinterfacewillbebuiltofseveralblocksthatshowthestateofeachsensor. Toseethatonesensorisactive,wewillsimplychangethecoloroftheindicatorfromgraytoorange. Thisisthecodeforthesensors:

.row.voffset

.col-md-6

.display#temperatureDisplayTemperature:

.col-md-6

.display#humidityDisplayHumidity:

.row

.col-md-6

.display#lightDisplayLightlevel:

.col-md-6

.status#statusStationOffline

Now,wearegoingtohavealookatthecodeinsidetheinterface.jsfile,whichdefineshowtheinterfaceoftheprojectisworking. ItwillmakethequeriestotheboardviatheNode.jsserver,andupdatetheinterfaceaccordingly. Thisfileislocatedinthepublic/jsfolderoftheinterface. Thisisthecompletecodeforthisfile:

vardevices=[];

$.get('/devices',function(json_data){

devices=json_data;

});


functionupdateSensors(){

//Updatelightlevelandstatus

$.get('/'+devices[0].name+'/light',function(json_data){

console.log(json_data.light);

$("#lightDisplay").html("Lightlevel:"+json_data.light+"%");

//Updatestatus

if(json_data.connected==1){

$("#status").html("StationOnline");

$("#status").css("color","green");

}

else{

$("#status").html("StationOffline");

$("#status").css("color","red");

}

$.get('/'+devices[0].name+'/temperature',function(json_data){

$("#temperatureDisplay").html("Temperature:"+json_data.temperature+"°C");

$.get('/'+devices[0].name+'/humidity',function(json_data){

$("#humidityDisplay").html("Humidity:"+json_data.humidity+"%");

});

});

});

}

setTimeout(updateSensors,500);

setInterval(updateSensors,5000);

});

ItstartsbydefiningthatweareusingSerialcommunications,andspecifyingwhichSerialportisusedandtheSerialspeed:

type='serial';

address='/dev/cu.AdafruitEZ-Link06d5-SPP';

speed=115200;

Notethathereyouwillhavetomodifythe“address”variablewithyourownSerialportaddressoftheBluetoothmoduleyouareusing.

ThemainpartofthisJavaScriptfileconsistsincontinuouslyrequestingthevalueofthedifferentmeasurementvariablesontheboard,bysendingqueriesviatheaRESTAPI.ThisisdoneinsideasetInterval()function:


Insidethisfunction,wesendarequestviaourcomputerBluetoothconnection. Forexample,togetthelightlevelmeasuredbytheArduinoboard,wesendthesame/lightcommandthatweusedbefore:


TheaRESTlibraryalwaysreturndatainaJSONcontainer,soitisreallyeasytoaccessthisdatawithinJavaScript. Whenwehavethisdata,wecanupdatethecorrespondingdisplayaccordingly:


Thesameisdonewiththetemperature&humiditymeasurements.

Wealsoneedtoknowifthestationisonlineornot. Todoso,wereadthefieldcalled“connected”whenameasurementiscomingback,andweupdatethecorrespondingdisplayinsidetheinterface:


$("#status").html("StationOnline");


}

else{

$("#status").html("StationOffline");


}

Afterthat,weclosethesetInterval()function,repeatingthisloopevery5seconds.



It’snowtimetotesttheinterface. MakesurethatyoudownloadallthefilesfromtheGitHubrepository,andupdatethecodewithyourowndataifnecessary,liketheSerialportcorrespondingtoyourBluetoothmodule. Also,makesurethattheArduinoboardisprogrammedwiththecodewesawearlierinthischapter.

Then,gotothefolderoftheinterfacewithaterminal,andtypethefollowingcommandtoinstalltheaREST,expressandJademodules:

sudonpminstallarestjadeexpress

NotethatifyouareunderWindows,youhavetoleaveoutthesudoinfrontofthecommands,anditisrecommendedtousetheNode.jscommandprompt. Finally,youcanstarttheNode.jsserverbytyping:

nodeapp.js


Listeningonport3000

Youcannowgototheyourwebbrowser,andtype:

localhost:3000

Afterawhile(theBluetooth2.1connectioncanbeprettyslow),youshouldseetheinterfaceoftheweatherstationbeingdisplayed:

YoucanofcoursedoublecheckwiththedisplayofthemeasurementsontheLCDscreen,tobesurethattheymatchwithwhattheinterfaceisdisplaying.

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyoudownloadedthelatestversionofthecodefromtheGitHubrepositoryofthebook. Alsomadesurethatyoucorrectlymodifiedthefilestoputyourownsettings,liketheSerialportforyourBluetoothmodule. Finally,makesuretoinstalltherequiredNode.jsmoduleswithnpmbeforestartingthewebinterface.


5.6 HowtoGoFurther

Let’ssummarizewhatwelearnedinthisproject. WetooktheprojectwealreadybuiltinChapter2andaddedwirelesscapabilitiestoitusingBluetooth. WelearnedhowtointerfaceaBluetoothmodulewithArduino,andbuildawirelessweatherstationwithit.Wewereabletomonitorthemeasurementsmadebytheweatherstationfromyourwebbrowser.

Thereareofcoursemanywaystogofurtherwiththisproject. Ofcourse,youcanaddmanydifferentweatherstationinyourhome. BecauseeachBluetoothmodulehasadifferentname(asadifferentSerialport),youcanusewhatyoulearnedinthischaptertoputthesestationseverywhereinyourhome.

Youcanalsoaddmoresensorstoeachofthesestations. Forexample,tomaketheprojectevenclosetoacommercialweatherstation,youcanaddapressuresensor,forexamplebasedontheBMP180chip. Thiswillallowyoutomeasuretheatmosphericpressure,butalsotellyouthealtitudeoftheweatherstation. Youcanalsoaddananemometertotheproject,tomeasurewindspeedifyouareusingthestationoutside.

Chapter6

ControllingLampsviaWiFiInthischapter,wearegoingtoupgradeanotherprojectwebuiltbefore:thesmartlampprojectfromChapter3. WearegoingtoremovetheLCDscreenthatweusedtodisplaythestatusofthelamp,andinsteadaddaWiFimoduletotheproject.

Youwillthenbeabletocontrolyourlampremotelyfromyourcomputer,butalsofromanydeviceconnectedonyourlocalWiFinetwork. Usingtheinterfacethatwearegoingtobuild,you’llalsobeabletomonitorthepowerconsumptionofthelamp,andcheckthevalueoftheambientlightlevel. Finally,youwillalsobeabletocreateyourownrulesbasedonthemeasureddata,forexampletoautomaticallyswitchthelampoffwhentheambientlightlevelgoesaboveagivenvalue. Let’sdivein!


Forthisproject,youwillofcourseneedanArduinoUnoboard. YoucanalsouseotherArduinoboardslikeanArduinoMegaorLeonardo,itwillworkjustfineaswell.

Fortherelaymodule,Iuseda5VrelaymodulefromPolulu,whichnicelyintegratesarelayonaboard,alongwithalltherequiredcomponentstocontroltherelayfromtheArduinoboard. ThisisapictureoftherelaymoduleIused:

Tomeasurethecurrentflowingthroughthelamp,IusedaboardbasedontheAC712sensorfromITeadStudio. ThissensorisreallyeasytousewithArduino,asitreturnsavoltagethatisproportionaltothemeasuredcurrent. Withthecorrectformula,wewilltheninferthecurrentflowingthroughthelampfromthevoltagemeasuredbytheArduinoboard. Ofcourse,youcanuseotherboardsbasedonthesamesensor. ThisisapictureoftheboardIusedforthisproject:


Then,youneedaWiFimodulebasedontheCC3000WiFichip. Therearealsomanyalternativestodothat. WhatIrecommendisusingtheAdafruitCC3000breakoutboard,whichistheonlyoneItestedthatworkedwithoutproblem. Itisniceandcompact,hasvoltageregulatorsonboard,aswellasanonboardantenna. ItriedtheofficialTICC3000board,butitneverworkedproperly,andyouhavetheuselevelshiftersaswell(theCC3000workswith3.3V,andtheArduinoUnowith5V). Theotheralternativeistomakeyourownbreakoutboard,therearemanyPCBlayoutavailableonline.

Toconnecttothelamptotheproject,Iusedastandardpairofpowerplugswithbarecablesattheend,withonefemalesocket(toplugthelampin)andonemalesocket(toplugitintothepowersocketinthewall). ThisisapictureofthecablesIused:

Finally,Iusedabreadboardandsomejumperwirestomakethedifferentelectricalconnections.

Thisisalistofallcomponentsusedinthisproject,alongwithlinkstopurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)Relaymodule(http://www.pololu.com/product/2480)Currentsensor(http://imall.iteadstudio.com/im120710011.html)Photocell(http://www.adafruit.com/product/161)10kOhmresistor(https://www.sparkfun.com/products/8374)CC3000WiFibreakoutboard(http://www.adafruit.com/products/1469)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

Onthesoftwareside,youneedtohavethelatestversionoftheArduinoIDEinstalledonyourcomputer,aswellastheaRESTlibraryforArduinowhichyoucanfindatthefollowinglink:


ThisprojectalsorequireshavingtheCC3000chiplibrary:

https://github.com/adafruit/Adafruit_CC3000_Library

AndtheCC3000mDNSlibrary:






http://www.adafruit.com/products/1469





https://github.com/adafruit/CC3000_MDNS



6.2 BuildingtheProject

Let’snowassemblethehardwareforthisproject. Asforthepreviousprojectusingarelay,wewilldosointwoparts. WewillfirstconnectthedifferentcomponentsliketherelaymoduletotheArduinoboard,andthenwewillconnectthelamptotheproject.

Thehardwareconnectionsforthefirstpartareactuallyquitesimple:wehavetoconnecttherelaymodule,thecurrentsensor,theWiFimoduleandthephotocell. First,connecttheArduinoUno+5Vpintotheredrailonthebreadboard,andthegroundpintothebluerail.

Forthephotocell,firstplacethecellinserieswiththe10kOhmresistoronthebreadboard. Then,connecttheotherendofthephotocelltotheredrailonthebreadboard,andtheotherendoftheresistortotheground. Finally,connectthecommonpinoftheresistor&thephotocelltotheArduinoUnoanalogpinA0.

Now,theWiFimodule. First,connecttheIRQpinoftheCC3000boardtopinnumber3oftheArduinoboard,VBATtopin5,andCStopin10. Then,youneedtoconnecttheSPIpinstotheArduinoboard:MOSI,MISO,andCLKgotopins11,12,and13,respectively. Finally,takecareofthepowersupply:VingoestotheArduino5V(redpowerrail),andGNDtoGND(bluepowerrail).

Thisisaschematicoftheproject,withouttherelaymoduleandcurrentsensorconnectedyet:


Fortherelaymodule,therearethreepinsyouneedtoconnect:VCC,GNDandSIG.VCCneedstogotheArduino5Vpin,soconnectittotheredpowerrail. GNDgoestotheArduinogroundpin,sotothebluepowerrail. Finally,connecttheSIGpintopinnumber8oftheArduinoboard.

Itisactuallysimilarforthecurrentsensormodule. Ithasthreepins:VCC,GND,andOUT.Asfortherelay,VCCneedstogotheArduino5Vpin,soconnectittotheredpowerrail. GNDgoestotheArduinogroundpin,sotothebluepowerrail. Then,connecttheOUTpintotheanalogpinA1oftheArduinoboard.

Thisisapictureofthefullyassembledproject,withoutthelampconnectedyet:

Wearenowgoingtoconnectthelamptothehardwarewealreadyassembled. Basically,theideaistohavethemainpowersupply(comingfromthepowersocketinthewall)goingtotherelay,thentothecurrentsensor,andfinallytothelamp. Followthisschematictomaketherequiredconnections:


Asitimpliesdangerousvoltagelevels(110vor230vdependingonwhereyouareintheworld),youshouldtakesomeprecautationsatthispoint,thatyoucanfindintheintroductionofthisbook. Ofcourse,youcanmake&testthewholeprojectofthischapterwithoutconnectinganyhigh-powerdevice.

6.3 TestingtheWiFiModule

Beforewebuildourwirelesssmartlamp,wearefirstgoingtocheckthatthemostimportantcomponentoftheprojectisworking:theWiFimodule. WearegoingtowriteanArduinosketchthatinitializesthechip,connectstoyourlocalWiFinetwork,anddisplaytheIPaddressofthemodule,meaningthatitwassuccessfullyconnectedtothenetwork. Thisisthecompletecodeforthispart:

//CodeforthetesttheWiFimodule

//Importrequiredlibraries

#include<Adafruit_CC3000.h>

#include<SPI.h>

//ThesearethepinsfortheCC3000chipifyouareusingabreakoutboard

#defineADAFRUIT_CC3000_IRQ3

#defineADAFRUIT_CC3000_VBAT5

#defineADAFRUIT_CC3000_CS10

//CreateCC3000instance

Adafruit_CC3000cc3000=Adafruit_CC3000(ADAFRUIT_CC3000_CS,

ADAFRUIT_CC3000_IRQ,ADAFRUIT_CC3000_VBAT,SPI_CLOCK_DIV2);

//YourWiFiSSIDandpassword

#defineWLAN_SSID"yourSSID"

#defineWLAN_PASS"yourPassword"

#defineWLAN_SECURITYWLAN_SEC_WPA2

voidsetup(void)

{

//StartSerial


//SetupCC3000andgetconnectedtothewirelessnetwork.

Serial.println("Initializingchip…");

if(!cc3000.begin())

{

while(1);

}

//ConnecttoWiFi

Serial.println("ConnectingtoWiFinetwork…");

if(!cc3000.connectToAP(WLAN_SSID,WLAN_PASS,WLAN_SECURITY)){

while(1);

}

while(!cc3000.checkDHCP())

{

delay(100);

}

Serial.println("Connected!");

//Displayconnectiondetails

displayConnectionDetails();

Serial.println(F("Testcompleted"));

}

voidloop(){

}


booldisplayConnectionDetails(void)

{

uint32_tipAddress,netmask,gateway,dhcpserv,dnsserv;

if(!cc3000.getIPAddress(&ipAddress,&netmask,&gateway,&dhcpserv,&dnsserv))

{

Serial.println(F("UnabletoretrievetheIPAddress!\r\n"));

returnfalse;

}

else

{

Serial.print(F("\nIPAddr:"));cc3000.printIPdotsRev(ipAddress);

Serial.print(F("\nNetmask:"));cc3000.printIPdotsRev(netmask);

Serial.print(F("\nGateway:"));cc3000.printIPdotsRev(gateway);

Serial.print(F("\nDHCPsrv:"));cc3000.printIPdotsRev(dhcpserv);

Serial.print(F("\nDNSserv:"));cc3000.printIPdotsRev(dnsserv);

Serial.println();

returntrue;

}

}

ItstartsbyincludingtherequiredlibrariesfortheCC3000chip:


#include<SPI.h>

AnddefiningthepinsonwhichtheCC3000moduleisconnectedto:




Then,wecancreateaninstanceoftheCC3000WiFichip:



Now,youwillneedtomodifythesketchtoenteryourownSSIDnetworkname,andtheassociatedpassword. IfyournetworkisnotusingWPA2authentication,youwillalsohavetochangethissecurityparameter:




Now,inthesetup()functionofthesketch,youneedtostarttheSerialportthatwewillusefordebuggingpurposes:


WecannowinitializetheCC3000WiFichip:

Serial.println("Initializingchip…");

if(!cc3000.begin())

{

while(1);

}

Afterthat,thesketchwilltrytoconnecttheWiFichiptotheWiFinetworkyoudefinedbefore,andgetanIPaddress:

Serial.println("ConnectingtoWiFinetwork…");


while(1);

}


{

delay(100);

}

Serial.println("Connected!");

Whenthechipisconnectedtothenetwork,wegettheIPaddressoftheWiFimoduleandprintitontheSerialportaswell. Finally,weprintthatthetestisnowcompleted:


Serial.println(F("Testcompleted"));



It’snowtimetotestthisfirstsketchoftheproject. MakesurethatyoumodifiedthesketchwithyourownWiFinetworknameandpassword. Then,uploadthesketchtotheArduinoboard,andopentheSerialmonitor. Thisiswhatyoushouldsee:

Initializingchip…

ConnectingtoWiFinetwork…

Connected!

IPAddr:192.168.1.100

Netmask:255.255.255.0

Gateway:192.168.1.1

DHCPsrv:192.168.1.1

DNSserv:192.168.0.254

Testcompleted

IfyoucanseeanIPaddress,congratulations,itmeansthattheWiFimoduleiscorrectlywiredandcanconnecttoyourWiFinetwork. Wecannowstartcodingtheremotecontrolpartofyoursmartlampproject.

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyoucorrectlywiredtheCC3000WiFimodule. Therearelotsofcablestoconnect,anditiseasytomixthemup. Also,makesurethatyourInternetconnectionisupandrunning,ortheWiFichipwon’tbeabletoconnecttothetestwebsite.


6.4 RemoteLampControl

Inthissection,wearegoingtobuildtheArduinosketchthatwewillusetocontrolthelampviaWiFi,andalsotogetthemeasuredambientlightlevel&powerconsumptionofthelamp.

Todoso,weareagaingoingtousetheaRESTlibrarysowecanhaveaneasyaccesstothepinsoftheArduinoboard,andtothevariablesinwhichthemeasurementsarestored.

AsthesketchisbuiltonthesketchthatweusedtotesttheWiFiconnections,Iwillonlydetailthecodethatwasaddedcomparedtotheprevioussketch. Thisisthecompletecodeforthispart:

//Codeforthewirelesssmartlampproject

#defineNUMBER_VARIABLES2

#defineNUMBER_FUNCTIONS1



#include<SPI.h>

#include<CC3000_MDNS.h>

#include<aREST.h>

//Relaystate


//Definemeasurementvariables





floatzero_sensor;







ADAFRUIT_CC3000_IRQ,ADAFRUIT_CC3000_VBAT);

//CreateaRESTinstance

aRESTrest=aREST();


#defineWLAN_SSID"KrakowskiePrzedm51m.15(flat15)"

#defineWLAN_PASS"KrK51flat15_1944_15"


//TheporttolistenforincomingTCPconnections

#defineLISTEN_PORT80

//Serverinstance

Adafruit_CC3000_ServerrestServer(LISTEN_PORT);

//DNSresponderinstance

MDNSRespondermdns;

//VariablestobeexposedtotheAPI

intpower;

intlight;

voidsetup(void)

{

//StartSerial


//InitvariablesandexposethemtoRESTAPI


rest.variable("power",&power);

//Setrelay&ledpinstooutputs


//Calibratesensorwithnullcurrent



rest.set_id("001");

rest.set_name("smart_lamp");


if(!cc3000.begin())

{

while(1);

}


while(1);

}


{

delay(100);

}

//StartmulticastDNSresponder

if(!mdns.begin("arduino",cc3000)){

while(1);

}



//Startserver

restServer.begin();

Serial.println(F("Listeningforconnections…"));

}

voidloop(){

//Measurelightlevel



//Performpowermeasurement


//Converttocurrent




power=(int)effective_power;

//HandleanymulticastDNSrequests

mdns.update();

//HandleRESTcalls

Adafruit_CC3000_ClientRefclient=restServer.available();

rest.handle(client);

}

booldisplayConnectionDetails(void)

{

uint32_tipAddress,netmask,gateway,dhcpserv,dnsserv;

if(!cc3000.getIPAddress(&ipAddress,&netmask,&gateway,&dhcpserv,&dnsserv))

{

Serial.println(F("UnabletoretrievetheIPAddress!\r\n"));

returnfalse;

}

else

{

Serial.print(F("\nIPAddr:"));cc3000.printIPdotsRev(ipAddress);

Serial.print(F("\nNetmask:"));cc3000.printIPdotsRev(netmask);

Serial.print(F("\nGateway:"));cc3000.printIPdotsRev(gateway);

Serial.print(F("\nDHCPsrv:"));cc3000.printIPdotsRev(dhcpserv);

Serial.print(F("\nDNSserv:"));cc3000.printIPdotsRev(dnsserv);

Serial.println();

returntrue;

}

}

//Getthereadingfromthecurrentsensor

floatgetSensorValue(intpin)

{

intsensorValue;

floatavgSensor=0;

intnb_measurements=100;

for(inti=0;i<nb_measurements;i++){

sensorValue=analogRead(pin);

avgSensor=avgSensor+float(sensorValue);

}

avgSensor=avgSensor/float(nb_measurements);

returnavgSensor;

}

Itstartsbyincludingalltherequiredlibraries:


#include<SPI.h>


#include<aREST.h>

Anddeclaringthepinonwhichtherelaymoduleisconnected:


Then,wedeclarethedifferentvariablesthatarerequiredforthepowermeasurementpart:





floatzero_sensor;

Then,wecreatetheinstanceoftheaRESTobjectthatwewillusetohandletherequestscomingviatheWiFiconnection:

aRESTrest=aREST();

WealsoneedtodefineonwhichportwewanttotheWiFichiptolistento. Forconvenience,wewillusetheport80,soyoucandirectlycommandyourArduinoboardfromawebbrowser:


WealsocreateaninstanceoftheCC3000server:


WealsoneedtocreateaninstanceoftheMDNSserver,sowecanaccesstheArduinoboardwithouthavingtotypetheboardIPaddresstoaccessit:

MDNSRespondermdns;

Finally,wedeclaretwovariablesthatwillcontainthemeasurementsofthepowerconsumptionandthelightlevel:

intpower;

intlight;

Now,inthesetup()functionofthesketch,wefirstexposethetwomeasurementvariablestotheRESTAPIsowecanaccessthemfromtheoutsideworldviaWiFi:


rest.variable("power",&power);

Afterthat,wedeclaretherelaypinasanoutput:


Wealsouseafunctionthataveragesthemeasurementsofthecurrentsensortogetthesensor’sreadingatwhichthecurrentisnull:


WecanalsosetanameandanIDforthedevice,thatwillbereturnedateachcalloftheboardviatheaRESTAPI:

rest.set_id("001");

rest.set_name("smart_lamp");

Afterthisstep,wesetanamefortheArduinoboardonthenetwork,forexample“arduino”. Thismeansthattheboardwillbeaccessiblebythenamearduino.localonyourlocalnetwork:


while(1);

}

Finally,stillinthesetup()functionwestarttheCC3000serverandwaitforincomingconnections:

restServer.begin();


Intheloop()functionofthesketch,wefirstgetthevalueoftheambientlightlevel,expressedin%:



Wealsogetthereadingcomingfromthecurrentsensor,againbyusingafunctiontoaveragetheresultoverseveralmeasurements:


Then,wecancalculatethepowerfromthemeasuredcurrent:




power=(int)effective_power;

Afterthat,weupdatetheMDNSserver:

mdns.update();

AndprocessanyincomingconnectionusingtheaRESTlibrary:





It’snowtimetotestthissketchonourproject. DownloadthecodefromtheGitHubrepository,andmakesurethatyoumodifythenameandthepasswordoftheWiFinetworkonwhichtheWiFichipwillconnectto. Then,uploadthecodetotheArduinoboard,andopentheSerialmonitor. Thisiswhatyoushouldsee:

Listeningforconnections…

Now,closetheSerialmonitor,andopenyourwebbrowser. YoucannowmakedirectcallstotheRESTAPIrunningontheboardtocontrolthepinsoftheArduinoboard. Forexample,toturnthelampon,justtype:

http://arduino.local/digital/8/1

Youshouldheartherelayswitching,thelampshouldturnonandyoushouldhaveaconfirmationmessageinsideyourbrowser:


PinD8setto1

Toswitchthelampoffagain,justtype:


NotethatthesecommandswillworkfromanydevicesconnecttothesamelocalnetworkastheArduinoboard. Forexample,youcanuseyoursmartphonetocontrolyourArduinoboardwiththesamecommands.

Ifitdoesn’twork,thefirstthingtodoistousetheIPaddressoftheboardinplaceofthearduino.localname. YoucangettheIPaddressbylookingatthemessagesdisplayedontheSerialmonitorwhenstartingtheproject.

Ifitisstillnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatallthehardwarecomponentsoftheprojectsarecorrectlywired,aswesawearlierinthechapter. Then,makesurethatyoudownloaded&installedtherequiredlibrariesforthisproject,especiallytheaRESTlibrary.

6.5 BuildingtheSmartLampInterface

Wearenowgoingtobuildtheinterfacethatyouwillusetocontroltheprojectfromyourcomputer. Usingthisinterface,youwillbeabletocontrolthelampviaWiFi,butalsotoseeinreal-timethepowerconsumptionofthelampandtheambientlightlevelcomingfromthephotocell.

Notethatthispartissimilartowhatwedidinthepreviouschapterfortheinterface. Ifyoufeelconfidentwithit,youcanskipthebeginningofthecodewalkthrough.


//Module


varapp=express();

//Defineport

varport=3000;

//Viewengine


//Setpublicfolder


//Rest


rest.addDevice('http','192.168.1.103');

//Serveinterface



});

//Startserver

app.listen(port);





varapp=express();

varport=3000;

Wealsoneedtotelloursoftwarewheretolookforthegraphicalinterfacefilesthatwearegoingtocodelater,andwealsodefineJadeasourdefaultviewengine:



Wealsoneedtousethenode-aRESTmodule,thatwillhandleallthecommunicationsbetweentheinterfaceandoursmartlamp. AtthispointyoualsoneedtoentertheIPaddressofyourWiFichip:



Now,wearegoingtobuildthemainrouteforourserver. WedefinethisroutebylinkingtherootURLoftheservertotheinterfaceoftheproject:



});


app.listen(port);



doctype

html

head

titleSmartLamp






body

.container

h1SmartLamp

.row.voffset

.col-md-6

button.btn.btn-block.btn-lg.btn-primary#1On

.col-md-6

button.btn.btn-block.btn-lg.btn-danger#2Off

.row

.col-md-4

h3#powerDisplayPower:

.col-md-4

h3#lightDisplayLightlevel:

.col-md-4

h3#statusOffline




WealsousetheTwitterBootstrapframeworktogiveabetterlookatourinterface:




Then,weneedtocreatetwobuttons:onetoturntherelayonandthereforeswitchonthelight,andanotheronetoswitchthelightoffagain. Thisisthecodeforbothbuttons:

.col-md-6

button.btn.btn-block.btn-lg.btn-primary#1On

.col-md-6

button.btn.btn-block.btn-lg.btn-danger#2Off

WewilldefineintheJavaScriptfileofthisprojecthowtheclicksonthesebuttonsarehandled.

Finally,wealsoneedtocreatetextfieldstodisplaythedifferentmeasurementsmadebyourArduinoproject,likethepowerandthelightlevel. Wealsocreateoneindicatortocheckthattheprojectisonline:

.col-md-4


.col-md-4


.col-md-4

h3#statusOffline

Now,wearegoingtoseethecontentsoftheinterface.jsfile,locatedinthepublic/jsfolderoftheproject. Thisisthecompletecodeforthisfile:

vardevices=[];

$.get('/devices',function(json_data){

devices=json_data;

});


//Updatesensorsandrepeatevery5seconds



//Functiontocontrolthelamp

$('#1').click(function(){

$.get('/'+devices[0].name+'/digital/8/1');

});



});


//Updatelightlevel



//Updatestatus


$("#status").html("LampOnline");


}

else{

$("#status").html("LampOffline");


}

//Updatepower

$.get('/'+devices[0].name+'/power',function(json_data){

$("#powerDisplay").html("Power:"+json_data.power+"W");

});

});

}

});

Therearetwomainpartsinthisfile:onethatdefineshowtheclicksonthebuttonsarehandled,andonewhichisheretorefreshthesensors.

Let’sseethepartaboutthebuttonsfirst. WebasicallyjustneedtolinkeachbuttonwiththecorrespondingdigitalWrite()commandoftheArduinoboard. Thisisdonebythefollowingpieceofcode:



});



});

Wealsoneedtocodethepartresponsibleofupdatingtheinterfacewiththemeasurementsdonebytheboard. Todoso,wearegoingtoquerythesemeasurementsfromtheboardatregularintervals,usingthesetIntervalfunctionofJavaScript:


Let’snowseethedetailsofthisupdateSensorsfunction. Togetthedatafromtheboard,forexamplethelightlevelmeasurement,weusethesamefunctionasbefore,bysendingthe/lightcommand. Howeverthistime,weusetheJSONdatareturned:


Withthisdata,wecanupdatethedisplayaccordingly:


ThisJSONdataalsocontainssomeinformationofthestatusoftheboard. Ifthe“connected”fieldispresent,wesetthestatusindicatortoonline,andsetthecolortogreen. Ifthedataisnotpresentorcorrupted,wesetittoofflineandapplyaredcolortothisindicator:




}

else{



}

Thesameisdoneforthepowermeasurementontheboard:



});

Thisfunctionisrepeatedevery5seconds. Thisalsowhereyoucandefineyourownfunctionstocontrolyourlampaccordinglytothemeasurements. Forexample,youcantellthelamptoautomaticallyswitchoffiftheambientlightlevelmeasurementisreachingagivenvalue.



It’snowtimetotesttheinterface. MakesurethatyoudownloadallthefilesfromtheGitHubrepository,andupdatethecodewithyourowndataifnecessary,liketheArduinoboardaddress. Also,makesurethattheArduinoboardisprogrammedwiththecodewesawearlierinthischapter.




sudonodeapp.js


Listeningonport3000


localhost:3000


Youshouldseetheinterfacebeingdisplayedinsideyourbrowser,withthebuttonstocontrolthelamp. Don’tworry,whenyourfirstopentheinterfacethelampshouldappearasofflineandtheindicatorshouldnotdisplayanydata. Afteramoment,theinterfacewillmakeaquerytotheArduinoboardandupdatethedataaccordingly:

Youcannowalsotestthedifferentbuttonsoftheinterface. Bydefault,thelampisturnedoff,soclickonthe“On”buttontoturnthelamponinstantly. Youshouldalsohearthe“click”comingfromtherelay. Whenthelampison,youshouldalsoseethatthepowermeasurementdisplayisupdatedaccordinglyontheinterface. Then,youcanclickonthe“Off”buttontoswitchthelampoffagain.

IfyoudefinedcodeintheJavaScriptfileoftheinterface,likeswitchingthelampoffautomaticallywhentheambientlightreachesagivenlevel,youshouldalsoseetheeffectsofthiscodeatthispoint.

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyoudownloadedthelatestversionofthecodefromtheGitHubrepositoryofthebook. Alsomadesurethatyoucorrectlymodifiedthefilestoputyourownsettings,liketheaddressofyourWiFimodule. Finally,makesuretoinstalltherequiredNode.jsmoduleswithnpmbeforestartingthewebinterface.

6.6 HowtoGoFurther

Let’ssummarizewhatwelearnedinthisproject. WetooktheprojectwealreadybuiltinChapter3andaddedWiFicapabilitiestoit. WelearnedhowtointerfaceaWiFichipwithArduino,andcontrolourprojectfromawebbrowser. Wewereabletocontrolthelampwirelessly,andaccessthedifferentmeasurementsfromyourbrowser. Finally,webuildasoftwarerunningonyourcomputertocontrolthewholeprojectfromagraphicalinterfacewithinyourwebbrowser.

Thereareofcoursemanywaystogofurtherwiththisproject. YoucanofcourseaddmoresensorstotheArduinoboardandaccessthesemeasurementswirelessly. Forexample,youcouldperfectlyaddatemperaturesensortotheprojectanddisplaythedataonthegraphicalinterfaceaswell. Youcanalsoaddasecondlamptothisproject,andcontrolbothlampsindependently.

Bychangingthecoderunningonyourcomputer,insidetheJavaScriptfile,youcanalsodefinemorecomplexbehaviorsforthelamp. Notonlyyoucancontrolthelampaccordingtothelightlevelmeasurements,butyoucanalsousethefactthatyourcomputerisconnectedtothewebtocreatemorecomplexbehaviors. Forexample,youcanautomaticallyswitchthelampoffafteragiventimeintheevening,andswitchitonagainintheearlymorningtowakeyouup.

Finally,youcanhaveseveraloftheseprojectsinyourhome,simplybygivingdifferentnamestoyourArduinoboards,andaddingmoreelementsinthegraphicalinterface. Youcanalsocreatemorebehaviorsandbuttonsforyourproject,forexampleabuttontoautomaticallyswitchoffallthelampsinyourhomewithasimpleclick.

Chapter7

BuildinganHomeAutomationSystemInthislastchapterofthebook,wearegoingtousewhatwelearnedinthepreviouschapterstobuildasmallhomeautomationsystem. ThissystemwillintegrateXBeemotionsensorsaswellasaWiFicontrolledlamp. Allofthesecomponentswillbecontrolledfromacentralinterface.

Wearefirstgoingtoseewhatisneededforthishomeautomationsystem. Then,wearegoingtobuildthedifferentmodules. Afteraquicktestofthemodules,wearegoingtobuildaninterfacesoyoucanmonitoreverythingfromyourcomputer. Finally,Iwillgiveyousomeadvicesabouthowtogofurtherandbuildmorecomplexhomeautomationsystems.


Let’sfirstseewhatweneedforthischapter. WebasicallyneedtobuildagivennumberofXBeemotionsensors,andoneWiFilampcontroller.

ThisisalistofallcomponentsforoneXBeemotionsensor,alongwithlinkstopurchasethemonline:

ArduinoUno(http://www.adafruit.com/product/50)PIRmotionsensor(https://www.adafruit.com/products/189)ArduinoXBeeshield(https://www.sparkfun.com/products/10854)XBeeSeries2modulewithwireantenna(https://www.sparkfun.com/products/11215)Jumperwires(http://www.adafruit.com/product/758)

TouseXBeeonyourcomputer,youwillalsoneedtogetthesecomponents:

USBXBeeexplorerboard(https://www.sparkfun.com/products/11812)XBeeSeries2modulewithwireantenna(https://www.sparkfun.com/products/11215)

FortheWiFilampcontroller,youwillneedthefollowingcomponents:

ArduinoUno(http://www.adafruit.com/product/50)Relaymodule(http://www.pololu.com/product/2480)Currentsensor(http://imall.iteadstudio.com/im120710011.html)Photocell(http://www.adafruit.com/product/161)10kOhmresistor(https://www.sparkfun.com/products/8374)CC3000WiFibreakoutboard(http://www.adafruit.com/products/1469)Breadboard(http://www.adafruit.com/product/64)Jumperwires(http://www.adafruit.com/product/758)

Onthesoftwareside,youneedtohavethelatestversionoftheArduinoIDEinstalledonyourcomputer,aswellastheaRESTlibraryforArduinowhichyoucanfindatthefollowinglink:


ThisprojectalsorequireshavingtheCC3000chiplibrary:














http://www.adafruit.com/products/1469





AndtheCC3000mDNSlibrary:




7.2 BuildingtheProject

Wearenowgoingtobuildthedifferentmodulesofourhomeautomationsystem. Aswealreadysawinpreviouschaptershowtoassemblethedifferentprojects,Iwillsimplyrefertothesechaptersforthecompleteinstructionsonhowtoassemblethehardware.

FortheXBeemotionsensors,pleaserefertoChapter4. Thisiswhatyoushouldendupwith:

FortheWiFilampcontroller,pleaserefertoChapter6. Thisiswhatyoushouldendupwith:

7.3 TestingtheModules

WearenowgoingtotestoneXBeemotionsensor,andtheWiFilampcontroller. Becausewealreadysawhowthesemodulesworkinpreviouschapters,wearedirectlygoingtotestthemwirelesslytocheckifeverythingisworkingfine.

First,hereisthecodefortheXBeemotionsensor:

//CodefortheXBeemotionsensor

//Libraries

#include<SPI.h>

#include<aREST.h>

//MotionsensorID

Stringxbee_id="1";


aRESTrest=aREST();

voidsetup(){

//StartSerial

Serial.begin(9600);



rest.set_name("motion_sensor");

}

voidloop(){

//HandleRESTcalls


}

Thissketchstartsbyincludingthecorrectlibrariesforthesketch:

#include<SPI.h>

#include<aREST.h>

WealsodefinetheIDofthesensor. Thisisreallyusefulifyouaremanymotionsensorsinyourhome,makesuretogivethemdifferentIDs:

Stringxbee_id="1";


aRESTrest=aREST();

Inthesetup()functionofthesketch,westarttheSerialport. Notethathere,itisreallyimportanttouseaspeedof9600asitisthedefaultspeedofXBeemodules:

Serial.begin(9600);

WealsosettheIDofthedevicethatwedefinedbefore:


Finally,intheloop()functionofthesketch,wesimplehandletherequestscomingfromtheSerialportusingtheaRESTlibrary:


It’snowtimetotestthissketch. UploadthesketchtheArduinoboard,andnowputtheswitchoftheXBeeshieldto“UART”sotheXBeemoduleisnowdirectlycommunicatingwiththeArduinomicrocontrollerviatheSerialport. NotethatifyouneedtoprogramtheArduinoboardagain,youneedtoswitchitbackto“DLINE”.

Now,youneedtolocatetheSerialportcorrespondingtotheXBeeexplorerboardconnectedtoyourcomputer. YoucandosobylookingattheTools>SerialPortmenuoftheArduinoIDE.Forexample,mineiscalled“/dev/cu.usbserial-A702LF8B”. Alsowriteitdownforlater,wewillneeditwhenbuildingtheinterfaceforourmotionsensors.

Now,opentheSerialmonitoroftheArduinoIDE.Makesurethatthespeedissetto9600.NotethatbecausewearenowconnecttotheXBeeexplorerboard,allcommandsthatyouaresendingnowarebeingsenttoallXBeemodulesinyourhome.

IntheSerialmonitor,type:

/id

ThiswillsimplyquerytheIDoftheallXBeeboardsthatareinyourhome. WhenItestedtheproject,Ihadonlyoneinmyhome. Itrespondedwith:

{"id":"1","name":"","connected":true}

Afterthisstep,wearegoingtoreadthestatusofthemotionsensor. Remember,itisconnectedtopinnumber8. Toreadfromthispin,simplytype:

/digital/8

Thesensorshouldanswerwiththefollowingmessage:

{"return_value":1,"id":"1","name":"","connected":true}

Ifthesensorisansweringtothequeriesatthispoint,itmeansthatitisworkingcorrectlyandthatyoucanaccessitwirelessly. AlsomakesuretoconfigureyourXBeemodulessotheyareallinthesameXBeePANID.RefertoChapter4formoreinformationonthis

topic.

WearenowgoingtotesttheWiFilampcontroller. Hereisthecodeforthismodule:

//DemooftheaRESTlibrarywiththeCC3000WiFichip



#include<SPI.h>


#include<aREST.h>









aRESTrest=aREST();





//TheporttolistenforincomingTCPconnections


//Serverinstance


//DNSresponderinstance

MDNSRespondermdns;

voidsetup(void)

{

//StartSerial



rest.set_id("2");

rest.set_name("relay_module");


if(!cc3000.begin())

{

while(1);

}


while(1);

}


{

delay(100);

}

//StartmulticastDNSresponder


while(1);

}

//Startserver

restServer.begin();


//InitDHTsensor&outputpin

pinMode(7,OUTPUT);

}

voidloop(){

//HandleanymulticastDNSrequests

mdns.update();

//HandleRESTcalls



}

Notethatforthelampcontroller,wearesimplygoingtousetherelaytoswitchthelamponandoff,andwewillnotusethedifferentsensorsoftheproject. Butyoucanintegratethemlaterinyourcentralinterfaceasanexercise.

Thecodestartsbyincludingalltherequiredlibraries:


#include<SPI.h>


#include<aREST.h>

Anddeclaringthepinonwhichtherelaymoduleisconnected:


Then,wecreatetheinstanceoftheaRESTobjectthatwewillusetohandletherequestscomingviatheWiFiconnection:

aRESTrest=aREST();

WealsoneedtodefineonwhichportwewanttotheWiFichiptolistento. Forconvenience,wewillusetheport80,soyoucandirectlycommandyourArduinoboardfromawebbrowser:


WealsocreateaninstanceoftheCC3000server:


WealsoneedtocreateaninstanceoftheMDNSserver,sowecanaccesstheArduinoboardwithouthavingtotypetheboardIPaddresstoaccessit:

MDNSRespondermdns;

Now,inthesetup()functionofthesketch,wedeclaretherelaypinasanoutput:


WecanalsosetanameandanIDforthedevice,thatwillbereturnedateachcallofthe

boardviatheRESTAPI:

rest.set_id("2");

rest.set_name("relay_module");

Afterthisstep,wesetanamefortheArduinoboardonthenetwork,forexample“arduino”. Thismeansthattheboardwillbeaccessiblebythenamearduino.localonyourlocalnetwork:


while(1);

}

Finally,stillinthesetup()functionwestarttheCC3000serverandwaitforincomingconnections:

restServer.begin();


Intheloop()functionofthesketch,weupdatetheMDNSserver:

mdns.update();

AndprocessanyincomingconnectionusingtheaRESTlibrary:



It’snowtimetotestthissketchonourproject. DownloadthecodefromtheGitHubrepository,andmakesurethatyoumodifythenameandthepasswordoftheWiFinetworkonwhichtheWiFichipwillconnectto. Then,uploadthecodetotheArduinoboard,andopentheSerialmonitor. Thisiswhatyoushouldsee:

Listeningforconnections…

Now,closetheSerialmonitor,andopenyourwebbrowser. YoucannowmakedirectcallstotheRESTAPIrunningontheboardtocontrolthepinsoftheArduinoboard. Forexample,toturnthelampon,justtype:


Youshouldheartherelayswitching,thelampshouldturnonandyoushouldhaveaconfirmationmessageinsideyourbrowser:

PinD8setto1

Toswitchthelampoffagain,justtype:

7.4 BuildingtheCentralInterface

Wearenowgoingtobuildtheinterfacethatyouwillusetocontrolthewholehomeautomationsystemfromyourcomputer. Usingthisinterface,youwillbeabletocontrolthelampviaWiFi,andgetreadingsfromtheXBeemotionsensors,allfromthesamewebpage.

Notethatthispartissimilartowhatwedidinthepreviouschaptersfortheinterface. Ifyoufeelconfidentwithit,youcanskipthebeginningofthecodewalkthrough.


//Module


varapp=express();

//Defineport

varport=3000;

//Viewengine


//Setpublicfolder


//Rest




//Serveinterface




});

//Startserver

app.listen(port);





varapp=express();

varport=3000;

Wealsoneedtotelloursoftwarewheretolookforthegraphicalinterfacefilesthatwearegoingtocodelater,andwealsodefineJadeasourdefaultviewengine:



Atthispoint,wealsoimportthenode-aRESTmodule,thatwillhandleallthecommunicationbetweentheinterface,theXBeemodules,andtheWiFichip. Here,wealsoneedtodefinetheSerialportonwhichtheXBeeexplorermoduleisconnectedto,andtheIPaddressoftheWiFichip:




Now,wearegoingtobuildthemainrouteofourserver. WedefinethisroutebylinkingtherootURLofourservertothecorrespondingJadefile. Becausewewanttobuildtheinterfaceautomaticallydependingonhowmanydevicesarepresent,weneedtogetallthedevicesfirst,andthentransmitthisdatatotheJadefilesoitcanberenderedcorrectly:




});


app.listen(port);



doctype

html

head

titleHomeAutomationSystem






body

.container

h1.text-centerHomeAutomationSystem

.row.voffset

h2LampControl

.row

.col-md-6

button.btn.btn-block.btn-primary.btn-lg#lamp1On

.col-md-6

button.btn.btn-block.btn-danger.btn-lg#lamp2Off

.row

.col-md-4


.col-md-4


.col-md-4

h3#statusOffline

.row.voffset

h2XBeeMotionSensors

if(devices!='[]')

eachdeviceindevices


.row

.col-md-4


.col-md-4





WealsousetheTwitterBootstrapframeworktogiveabetterlookatourinterface:




Afterthat,youcanseetwomainblocksinthisfile. ThefirstoneistocreatetwobuttonstocontrolthelampviaWiFi,andtodisplaydatafromthesensors:

.row.voffset

h2LampControl

.row

.col-md-6

button.btn.btn-block.btn-primary.btn-lg#lamp1On

.col-md-6

button.btn.btn-block.btn-danger.btn-lg#lamp2Off

.row

.col-md-4


.col-md-4


.col-md-4

h3#statusOffline

ThesecondblockistodisplaythestatusoftheXBeemotionsensors:

if(devices!='[]')

eachdeviceindevices


.row

.col-md-4


.col-md-4


Now,wearegoingtoseethecontentsoftheinterface.jsfile,locatedinthepublic/jsfolderoftheproject. Thisisthecompletecodeforthisfile:


$.get('/devices',function(devices){

//Updatesensorsandrepeatevery5seconds



//Functiontocontrolthelamp

$('#lamp1').click(function(){


});

$('#lamp2').click(function(){


});

//Updatelampsensors


//Updatelightlevel



//Updatestatus




}

else{



}

//Updatepower



});

});

}

//Setinputsformotionsensors


//Getdevice


//Setinput

if(device.type=='xbee'){

$.get('/'+device.name+'/mode/8/i');

}

}



//Getdevice


//Getdata

if(device.type=='xbee'){


//Updatedisplay




}

else{



}

});

}

}

},2000);

});

});

Youwillseethatthiscodebasicallycombinesthefunctionswesawinthemotionsensorschapter,andinthesmartlampchapter.



It’snowtimetotesttheinterface. MakesurethatyoudownloadallthefilesfromtheGitHubrepository,andupdatethecodewithyourowndataifnecessary,liketheArduinoboardaddressandtheXBeeexplorerSerialport. Also,makesurethattheArduinoboardisprogrammedwiththecodewesawearlierinthischapter.




sudonodeapp.js


Listeningonport3000


localhost:3000

Youshouldseetheinterfacebeingdisplayedinsideyourbrowser,withthebuttonstocontrolthelamp,thesensordatafromthelamp,andthestateoftheXBeesensors. Trytopassyourhandinfrontofoneofthesensor,theinterfaceshouldchangeaccordingly:


Youcanalsoclickononeofthebuttons,andthelampshouldturnonoroffinstantly.

Ifitisnotworkingatthispoint,thereareseveralthingsyoucancheck. First,makesurethatyoudownloadedthelatestversionofthecodefromtheGitHubrepositoryofthebook. Alsomadesurethatyoucorrectlymodifiedthefilestoputyourownsettings,liketheSerialportforyourBluetoothmodule,andtheaddressoftheWiFimodule. Finally,makesuretoinstalltherequiredNode.jsmoduleswithnpmbeforestartingthewebinterface.

7.5 HowtoGoFurther

Let’ssummarizewhatwelearnedinthisproject. WetooktheprojectwealreadybuiltinChapter4andinChapter6tobuildasmallhomeautomationsystem. WebuiltseveralXBeemotionsensors,andaWiFilampcontroller. Wetestedthesemodules,andthenintegratedeverythinginoneuniqueinterfacesowecanmonitoreverythingfromacentralplace.

Thereareofcoursemanywaystogofurtherwiththisproject. Withnearlythesamecode,youcanaddmoreWiFilampcontrollers,andalsomoreXBeemotionsensors. Youcanalsoaddmoresensorstotheproject.

Youcanalsodefinemorecomplexbehaviorsintothesystem,forexamplelinkingthemeasurementofthemotionsensortotheactivationoftherelay. Iftheyarelocatedinthesameroom,youcansetthesystemsotherelayautomaticallyturnsonwhenmotionisdetectedintheroom(forexampleintoilets).

Notethatitisnotrecommendedtomixmanywirelessmodulesinthesamesystem. Forexample,itisbettertouseWiFiforeveryactuators(relays),andXBeeforeverysensors(motion,temperature,humidity…).

Chapter8

Conclusion

8.1 Whatdidyoulearninthisbook?

Wearealreadyclosetotheendofthisbook,andIreallyhopedyouenjoyedreadingitasmuchasIenjoyedwritingitandrealizingalltheprojectscontainedinthebook. Let’ssummarizeeverythingyouhavelearnedbyreadingthisbook.

Inthefirstpartofthebook,wesawhowtointerfacesensorsandothercomponentswiththeArduinoplatformtobuildhomeautomationsystems.

Intheveryfirstchapter,youlearnedthebasicsoftheArduinoplatform,andyoualsolearnedhowyoucouldusethisplatformforhomeautomationprojects. WealsobuiltourveryfirsthomeautomationsystemwithArduino:asimplemotionsensorconnectedtoanalarm.

Thenextchapterwasallaboutlearningthebasicsofatypicalhomeautomationproject:howtomeasuredatafromsensorsusingArduino,andhowtodisplaytheseresultsonaLCDscreen.

Then,youlearnedhowtocontrolalampusingArduino. Weusedarelaytocontrolthislampatwill,andalsousedanothercomponenttoautomaticallymeasurethecurrent&powerconsumptionofthislamp. Wealsointegratedalightlevelsensortotheproject,sowecouldprogramthelamptoautomaticallyswitchonwhenthenightapproaches.

Afterthat,inthesecondpartofthebook,weusedwhatwelearnedinthefirstparttobuildwirelesshomeautomationsystemsbasedonArduino.

First,wetookthemotionsensorprojectthatwedevelopedearlierinthebook,andmonitoredthemotionsensorswirelesslyusingtheXBeetechnology. Withthisnewhardware,webuiltanarrayofmotionsensorsthatcanbedeployedinyourhome,andwemonitoredthemusingacentralinterfaceonyourcomputer.

Weusedthesameconcepttoaddwirelesscapabilitiestothetemperature,humidityandlightlevelsmeasurementproject. WeaddedaBluetoothmoduletotheproject,andwewereabletomonitorthemeasureddatafromawebbrowser.

Inthenextchapter,weaddedWiFitothelampcontrolproject,andwereabletocontrolalamp&monitoritsenergyconsumptionremotely. BecauseweusedWiFitodoso,wewerealsoabletocontrolthelampdirectlyfromasmartphoneortablet.

Finally,inthelastchapterofthebook,weusedeverythingwelearnedinthebooktobuildanhomeautomationsystembasedonseveralXBeemotionsensors&aWiFi-controlled

lamp. Wealsointegratedeverythingintoacentralsoftware,soyoucanmonitor&controlyourhomefromasingleinterface.

Ofcourse,throughthisentirebookyoudidn’tlearnonlyaboutArduinoandhomeautomation. YoualsoacquiredsolidknowledgeaboutotherprogramminglanguageslikeJavaScriptandHTML,whichcanbeusefulinmanyotherdomains.

8.2 Howtogofurther?

WithalltheknowledgeyouacquiredinthisbookabouttheArduinoplatformandhomeautomation,itisnowtimetogofurtherandbuildyourownhomeautomationsystems.Buttheessentialquestionis:howtostart?

Ifyou’renot100%confidentaboutyourskillsyet,thefirststepisreallytogothroughalltheprojectsofthisbookandtrytodothemagainyourselfwithoutthehelpofthebook.Thatwillreallygiveyoutheskillsandconfidencetobuildmoreprojects.

Mysecondadviceistostartsmall. Istheresomeprojectinyourhomeyoualwayswantedtodoandthatyoucouldn’tdobecausealackofskills? Nowisagoodtimetodoit. Butdon’tstartbydesigningandbuildingacompletesecuritysystemforyourhome! StartbyconnectingasensortoArduinotodetectifadoorisopenedforexample. Thenaddothersensors. Whenthisisworking,addaLCDscreenandsomebuttonstohaveabasicinterface. Thenconnectittoyourcomputerusingwhatyou’velearnedinthisbook. Andsoonenough,youwillhaveyourwholesecuritysystem.

Mylastadviceforyou:havefun! Ifyouchosetofollowtheprojectsofthisbook,itisprobablythatyouareinterestedinbuildingyourownhomeautomationsystemsinsteadofbuyingcommercialones,mainlybecauseyouareinterestedinexperimentingandhavingcontroloveryourinstallation. Andthebestwaytobuildbettersystemsistohavefundoingit. Itdoesn’tmatterifwhatyoubuiltisnotperfectthefirsttime:taketimetoexperiment,adjust,andplaywithwhatyoubuild. Thiswillboostyourconfidence,makeyouhappyandpushyoutoexperimentwithmoreandmorecomplexsystems.

Iwillfinishthisbookwithanopeningtothefutureofhomeautomationusingopen-sourcehardware. Iseemanytrendsinthefuturefromwhichthehomeautomationdomaincanreallybenefit.

Thefirstone,whichisamajortrendatthemomentthisbookwaswritten,is3Dprinting.Forthosewhodon’tknowwhat3Dprintingis,it’ssimplyatechniqueofbuildingobjectsby“printing”themlayer-by-layer. Thecoreofa3Dprinterisaprintingheadthatcanalsomoveupanddowniscontrolledbyaprocessortobuildtheexactreplicaofa3Dobjectthathasbeendesignedonacomputer. Thistechniqueallowsrapidprototypingofsmallobjectsandisalreadyusedbydesignerstoreducethetimetodevelopanewproduct.Comparedtotypicalfabricationtechniqueslikeinjectionmolding,3Dprintingismuchbettertoprototypesmallobjectsasitischeaperandthemachinecanstandonyourdesk.

Now,whatdoesitmeanforhomeautomationenthusiasts? Well,Ibelieveitwillbearealgamechangerinthefuture. Withwhatwesawinthisbook,youcanbuildabasicalarmsystemforyourhomethathavethesamefunctionalitiescomparedtoanalarmsystemthatyouwouldhaveboughtinastore. However,itstilllackssomethingcomparedtothecommercialsystem:youdon’thavethenicedesignoftheplasticprotectionandcasesthatcomeswiththecommercialsystem. Itisfineforprototypingandplayingaround,butitisnotniceifyouwanttobuildalongerlastinghomeautomationsystem.

AndIbelieve3Dprintingcanchangethat. Before,nobodycoulddesignhisorherowncasesforanalarmsystemorasensor. Youneededtobuildamold,whichwasveryexpensive,andthengotoafactorytobuildthepiecesforyoursystem. Butnowwe3Dprinting,itbecomespossible. Youcandesignthepartsonyourcomputer,andhavethembuiltonebyonebya3Dprinter,withareallylimitedcost. Therearemoreandmorespacesintheworldwhereyoucan“rent”a3Dprinterforalimitedamountoftimetoprintyourdesigns. Oneexampleisthefablabs,whereyoucanfindallsortoftoolstobuildobjects. Youcanfindalistoffabsatthisaddress:

http://fab.cba.mit.edu/about/labs/

Withthiskindoftechnologies,youcanreallybuildhomeautomationsystemsthatlookasprofessionalascommercialsystems.

AnothertrendIamcurrentlyseeingistheavailabilityofmoreconnectedobjects. ThistrendisusuallydenotedastheInternetofThings(IoT),whichsaysthatallobjectsinourhomeandeveninourlifeingeneralwillendupbeingconnectedtotheInternet. Westilllackthehardwareandanopenprotocoltostandardizeeverything,butthisisdefinitelysomethingwehearaboutmoreandmoreinthecomingyears.

Fortheworldofhomeautomationusingopen-sourcecomponents,thiswillalsohaveanimpact. Itisstillcomplicatedtoconnectanobject,forexampleasensor,totheweb,asyouhavetouseadedicatedshieldforArduinoforexample. However,moreandmoreboardsbasedontheArduinoplatformarecomingwithbuilt-inconnectivity. Andatthetimethisbookwaswritten,Arduinoactuallyhasseveralboardswithbuilt-inWiFiconnectivity,liketheArduinoYun. Ibelievethatwiththiskindofconnectedboards,itwillbeeasierandeasiertobuildconnectedhomeautomationsystemsthatintegratewithotherdevicesseamlessly.

http://fab.cba.mit.edu/about/labs/

Chapter9

ResourcesThefollowingisalistofthebestressourcesconcerningopen-sourcehomeautomationwithArduino. Iorganizedthischapterindifferentcategoriessoitiseasierforyoutofindtheinformationyouneed.

9.1 GeneralInformationaboutArduino

OpenHomeAutomation:Thecompanionwebsiteofthisbook,whereyouwillfindmanymoreprojectsusingArduino&open-sourcehardwaretobuildhomeautomationprojects.Arduino:thereferencewebsiteoftheArduinoplatform. EspeciallygoovertotheirfantasticforumstofindhelponyourArduinorelatedprojects.Instructables:Awebsitecontainingstep-by-stepprojects. Searchtherefor“Arduino”or“Homeautomation”andyouwillfindalotofexcitingprojects.AdafruitLearningSystem:Anonlinelearningplatformwithaselectionofhigh-qualitystep-by-steparticlesonmakingthingsingeneral. ManyprojectsusetheArduinoplatform,andsomeareabouthomeautomation.

http://www.openhomeautomation.net/

http://arduino.cc/

http://www.instructables.com/

https://learn.adafruit.com

9.2 Components

SparkFun:AwebsitesellingmanyArduinorelatedproducts. Alltheirproductsareopen-sourceandyoucandownloadthesourcefilesdirectlyfromtheirproductdescriptions.Adafruit:AcompanybasedinNewYorkthatsellshighqualityproductsfortheArduinoplatform.SeeedStudio:AChinesecompanythatsellsmanyoriginalproductsfortheArduinoplatform. TheyalsooffertheirownPCBproduction&assemblyservices.

https://www.sparkfun.com/

http://www.adafruit.com/

http://www.seeedstudio.com/

9.3 SuggestedReading

ProgrammingArduino:GettingStartedWithSketches:WrittenbySimonMonk,thisbookisaveryclearandpracticalintroductiontoArduino.ArduinoWorkshop:AHands-OnIntroduction:Awell-writtenbookwithmanysimpleprojectstolearnabouttheArduinoplatform.ArduinoCookbook:WrittenbyMichaelMargolis,thebookisanexcellentin-depthresourceabouttheArduinoplatform.

http://www.amazon.com/Programming-Arduino-Getting-Started-Sketches/dp/0071784225/ref=sr_1_1?s=books&ie=UTF8&qid=1405336117&sr=1-1&keywords=arduino

http://www.amazon.com/Arduino-Workshop-Hands--Introduction-Projects/dp/1593274483/ref=sr_1_3?s=books&ie=UTF8&qid=1405336117&sr=1-3&keywords=arduino

http://www.amazon.com/Arduino-Cookbook-Michael-Margolis/dp/1449313876/ref=sr_1_7?s=books&ie=UTF8&qid=1405336117&sr=1-7&keywords=arduino

TableofContents

FrontmatterChapter1Chapter2Chapter3Chapter4Chapter5Chapter6Chapter7Chapter8Chapter9

home automation with arduino: automate your … automation with arduino automate your home using...

Documents